Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and Other Technical Amendments

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

The Environmental Protection Agency (EPA) is amending the test procedures for heavy-duty engines and vehicles to improve accuracy and reduce testing burden. EPA is also making other regulatory amendments concerning light-duty vehicles, heavy-duty vehicles, highway motorcycles, locomotives, marine engines, other nonroad engines and vehicles, and stationary engines. These amendments affect the certification procedures for exhaust emission standards and related requirements. EPA is finalizing similar amendments for evaporative emission standards for nonroad equipment and portable fuel containers. The amendments increase compliance flexibility, harmonize with other requirements, add clarity, correct errors, and streamline the regulations. Given the nature of the amendments, they will have neither significant environmental impacts nor significant economic impacts for any sector.

DATES:

This final rule is effective on July 29, 2021. The incorporation by reference of certain publications listed in this regulation is approved by the Director of the Federal Register as of July 29, 2021.

ADDRESSES:

The EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2019-0307. All documents in the docket are listed on the www.regulations.gov website. Although listed in the index, some information is not publicly available, e.g., confidential business information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy at Air and Radiation Docket and Information Center, EPA Docket Center, EPA/DC, EPA WJC West Building, 1301 Constitution Ave. NW, Room 3334, Washington, DC. Note that the EPA Docket Center and Reading Room were closed to public visitors on March 31, 2020, to reduce the risk of transmitting COVID-19. The Docket Center staff will continue to provide remote customer service via email, phone, and webform. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742. For further information on EPA Docket Center services and the current status, go to https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT:

Alan Stout, Office of Transportation and Air Quality, Assessment and Standards Division, Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; telephone number: (734) 214-4805; email address: stout.alan@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information

II. Heavy-Duty Highway Amendments

A. Test Procedures and Compliance Model Changes

B. Heavy-Duty Engine GHG Emission Standards and Flexibility

C. Heavy-Duty Vehicle GHG Emission Standards and Flexibility

D. Onboard Diagnostics (“OBD”)

III. Other Amendments

A. Ethanol-Blend Test Fuels for Nonroad Spark-Ignition Engines and Vehicles, Highway Motorcycles, and Portable Fuel Containers

B. Removing Obsolete CFR Content

C. Certification Fees (40 CFR Part 1027)

D. Additional Amendments for Motor Vehicles and Motor Vehicle Engines (40 CFR Parts 85 and 86)

E. Additional Amendments for Locomotives (40 CFR Part 1033)

F. Additional Amendments for Land-Based Nonroad Diesel Engines (40 CFR Part 1039)

G. Additional Amendments for Marine Diesel Engines (40 CFR Parts 1042 and 1043)

H. Portable Fuel Containers (40 CFR Part 59)

I. Evaporative Emission Standards for Nonroad Spark-Ignition Engines and Equipment (40 CFR Part 1060)

J. Additional Amendments for Nonroad Spark-Ignition Engines at or Below 19 kW (40 CFR Part 1054)

K. Amendments for General Compliance Provisions (40 CFR Part 1068)

L. Other Requests for Comment

IV. Statutory Authority and Executive Order Reviews

I. General Information

Does this action apply to me?

This action relates to companies that manufacture, sell, or import into the United States new heavy-duty engines or Class 2b through 8 trucks, including combination tractors, vocational vehicles, and all types of buses. Vocational vehicles include municipal, commercial, and recreational vehicles. Additional amendments apply for different manufacturers of light-duty vehicles, light-duty trucks, highway motorcycles, stationary engines, and various types of nonroad engines, vehicles, and equipment. Regulated categories and entities include the following:

This list is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. If you have questions regarding the applicability of this action to a particular entity, consult the person listed in the FOR FURTHER INFORMATION CONTACT section.

What action is the Agency taking?

This action amends the regulations that implement our air pollutant emission standards for engines, vehicles and mobile equipment. The amendments include corrections, clarifications, and flexibilities for multiple types of vehicles, engines and equipment.

The majority of these amendments modify existing test procedures for heavy-duty highway engines and vehicles. These test procedure changes improve accuracy, and in some cases, reduce test burden. They mainly apply for measurement of greenhouse gas (GHG) pollutants (primarily CO2), though some apply for criteria pollutants (such as NO_X), as well. See Section II.A.

Additional heavy-duty highway amendments update EPA regulations to enhance implementation of existing emission standards. For example, some changes reduce the likelihood that manufacturers would need to duplicate certification efforts to comply with EPA, Canadian, and Californian standards. Some amendments make it easier for manufacturers to more fully account for the emission benefits of advanced emission control technology, which could provide them the opportunity to generate additional emission credits. These heavy-duty highway amendments are described in Section II.B.

This rule includes other amendments that are generally administrative or technical in nature and include amendments for nonroad engines and vehicles, stationary engines, and portable fuel containers. These amendments are described in Section III. Perhaps the most visible administrative amendment is the elimination of hundreds of pages of obsolete regulations, which is described in Section III.B.

EPA published a proposed rule on May 12, 2020 (85 FR 28140). This final rule follows from that proposal, with several adjustments that reflect EPA's consideration of comments received. Most of the proposed revisions from that document are addressed in this final rule. EPA is also issuing a new notice of proposed rulemaking to supplement the earlier proposed rule, published in the Proposed Rules section of this issue of the Federal Register, titled “Improvements for Heavy-Duty Engine and Vehicle Test Procedures,” docket number EPA-HQ-OAR-2019-0307; FRL-10018-51-OAR. In the supplemental proposal, EPA proposes further amendments concerning only certain specific aspects of the Greenhouse gas Emissions Model (GEM) (see Section II of the preamble to the supplemental proposal).

The proposed rule included requests for comment on a wide range of issues, including some broad areas where we were interested only in gathering information for potential future rulemaking(s). This preamble does not include a discussion of those comment areas where we are not taking any action in this final rule. The “Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and other Technical Amendments Response to Comments” document (“Response to Comments”) in the docket for this rulemaking includes a summary of the input received from commenters and EPA's responses.

In addition, we have prepared a docket memo with redline text to highlight all the changes to the regulations in the proposed rule. This is especially helpful for reviewing provisions that we are removing from the Code of Federal Regulations. For obsolete provisions we are removing, see especially 40 CFR 1027.105, 1033.150, 1042.145, 1045.145, 1048.145, 1051.145, 1054.145, and 1054.625. We prepared additional docket memos to show regulatory changes after the proposed rule.

What are the incremental costs and benefits of this action?

This action is limited in scope and does not include amendments that have significant economic or environmental impacts. EPA has therefore not estimated the potential costs or benefits of this final rule (and we did not for the proposal).

II. Heavy-Duty Highway Amendments

A. Test Procedures and Compliance Model Changes

Since the promulgation of the Phase 2 regulations, manufacturers have been revising their internal test procedures to ensure they will be able to comply with the new requirements that begin in model year 2021. In doing so, they have identified several areas in which the test procedure regulations could be improved (in terms of overall accuracy, repeatability and clarity) without changing the effective stringency of the standards.

EPA is making numerous changes to the test procedure regulations to address manufacturers' concerns and other issues we have identified. These changes are described below. The list includes numerous editorial changes that simply correct typographical/formatting errors or revise the text to improve clarity. Although these amendments are being made primarily in the context of heavy-duty engines and vehicles, the amendments to part 1065 will also apply to nonroad engines, and the amendments to part 1066 will also apply to light-duty vehicles. Since these amendments are mostly editorial or adding flexibility, they will not adversely impact these other sectors.

1. 40 CFR Part 1036 Test Procedures

EPA proposed several updates to the testing and measurement provisions of part 1036, subpart F, and appendices of part 1036 related to how to measure emissions from heavy-duty engines and requested comment on general improvements to the engine test procedures and compliance provisions (85 FR 28141). This section presents the changes we are adopting to engine test procedures after consideration of comments received. Additional details on some of these and other engine testing and measurement amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments. Amendments to other subparts of part 1036 (i.e., amendments not directly related to test procedures) are discussed in Section II.B.

These updates are primarily for the purposes of adding flexibility and reducing variability in test results. Additional information that led to and supports these changes arose from a test program at Southwest Research Institute (SwRI) that was jointly funded by EPA and the Truck and Engine Manufacturers Association (EMA).

We are generally finalizing revisions as proposed; however, some revisions include further changes and clarifications after consideration of public comments to better ensure clarity, accuracy and consistency with the intent of the proposed rule.

• Section 1036.501(g)—Providing a new paragraph (g) to specify duty cycles for testing model year (MY) 2016-2020 engines, including additional clarifications to the proposed amendment to refer to the steady-state duty cycle as the Supplemental Emission Test (“SET”) rather than the Ramped Modal Cycle (“RMC”) to avoid confusion as steady-state cycles are run as RMCs in many standard setting parts, and to change a reference for the Federal Test Procedure (“FTP”) duty cycle from appendix B of 40 CFR part 1036 to 40 CFR 1036.510 because 40 CFR 1036.510 gives an overview of the duty cycle and provides the reference to appendix B of 40 CFR part 1036.
• Section 1036.501(h)—Renumbering existing paragraph (g) concerning testing of MY 2021 and later engines as new paragraph (h), modifying paragraph (h)(1) to address restarting the engine during dynamometer testing for engines with stop-start technologies, and adding paragraph (h)(3) (shown as (h)(2) in the proposed rule) to cross-reference transient test cycle specifications, including additional clarifications in final paragraph (h)(2) to refer to the Supplemental Emission Test cycle to avoid confusion as steady-state cycles are run as RMCs in many standard setting parts and in paragraph (h)(2)(ii) that weighting factors for the Supplemental Emission Test are to be applied to CO2 to calculate the composite emission result.
• Section 1036.503—Migrating § 1036.510 to new § 1036.503, renumbering existing paragraph (d) as new paragraph (c), updating paragraphs (b) and (c)(1) through (3) and adding paragraphs (c)(4) and (5) and (d), including provisions to specify that the engine manufacturer must provide idle speed and torque to the vehicle manufacturer and to provide additional direction on handling data points for a low speed governor where the governor is active. We further modified proposed paragraph (b) to denote that there are four methods to generate fuel maps with the addition of the hybrid powertrain and hybrid engine testing procedures and to more clearly explain which method(s) apply to which application, paragraphs (b)(1) and (2) to add more specificity to which referenced paragraphs in § 1036.535 are applicable, paragraph (b)(3) to clarify that the option in § 1037.520(d)(2) is only allowed for hybrid powertrain testing and not powertrain testing in general, and added paragraph (b)(4) to include a method to perform hybrid engine testing. We also further updated paragraph (c)(1) to clarify how to measure torque curve for engines that have a rechargeable energy storage system (RESS) and for those that don't.
• Section 1036.505—Adding paragraph (b) to give direction on both engine and powertrain testing and modifying Table 1 to include vehicle speed and grade parameters to facilitate the hybrid powertrain testing option. We further modified the proposed language in this section by: Adding a new paragraph (b)(2)(v) to calculate curb mass for hybrid powertrain testing as this calculation is needed to determine the linear equivalent mass of rotational moment of inertias in clarified paragraph (b)(2)(vi), adding reference speed determination requirements for powertrain testing in paragraphs (c)(2)(i) and (ii) to address underspeed conditions in the hybrid powertrain SET testing, including a removal of default A, B, and C SET speeds and calculation of the A and B speeds based on C speed, modifying Table 1 further to include vehicle speed and grade parameters to facilitate the hybrid powertrain testing option so the road grade equation is now vehicle speed-dependent to address vehicle underspeed concerns corresponding to the determination and use of vehicle C speed, and replacing ramped modal cycle with supplemental emission test for the reason discussed in the first bullet of this subsection of the preamble.
• Section 1036.510—Providing a new section regarding transient testing of engines and hybrids to facilitate hybrid certification for both GHG and criteria pollutants.
• Section 1036.525(a)—Adding a clarification in the final rule that the hybrid engine testing procedure in this section applies only for model year 2014 to 2020 hybrid engines since the new hybrid powertrain and hybrid engine test procedure being adopted in this rulemaking will apply for model year 2021 and later engines.
• Section 1036.525(d)(4)(i)—Editorial revisions to equation and the addition of example calculations.
• Section 1036.527—Adding a section to provide a means to determine powertrain systems rated power and continuous rated power, to facilitate the hybrid and conventional powertrain testing options. This test procedure is applicable for powertrain testing defined in 40 CFR 1037.550 for both the engine and vehicle standards. We further modified the proposed language, including modifying how the test is carried out by reducing the number of test intervals from 9 to 1, paragraph (e) to address the determination of Psys for speed and torque measurements at different locations, with new paragraphs (g) and (h) to provide an improved method for determining continuous rated power and vehicle C speed, and addressed typographical errors.
• Section 1036.530(a), (b)(1)(i) and (ii), and (b)(2)(i) and (ii)—Updating carbon mass fraction determination to allow analysis by a single lab only to facilitate on-line analysis from pipeline supplied natural gas and adding the ASTM International method for determination of test fuel mass-specific energy content for natural gas. We have further modified the proposed language by clarifying in paragraph (a) that the infrequent regeneration adjustment factors (IRAF) are applied to CO2 emission results for all duty-cycles, not just cycle average engine fuel map results, and updating paragraph (b) to require test fuel mass-specific energy content and carbon mass fraction to be analyzed by at least three different labs and the median of all the results to be used in the calculation. We are also adding a recommendation that you screen your results to determine if additional observations are needed by performing an outlier test and provided critical values for this check. The critical values were determined as 1.27 times the method reproducibility R. The R value used for fuel mass-specific energy content is 0.234 which is the published R value for ASTM D4809 and the R value used for carbon mass fraction is 1.23, which was based on analysis of the fuel survey data for ASTM D5291 that was used in the Fuel Mapping Variability Study at SwRI.
• Section 1036.530 Table 1—Updating footnote format in table.
• Section 1036.535—Generally updating to improve the engine fuel mapping test procedures based on the jointly funded EPA-EMA test program. The overall result of these updates is to reduce the variability of the emission test results to reduce lab-to-lab variability. We further modified the proposed language by adding paragraph (h) to describe how EPA will determine the official fuel consumption rate during a confirmatory test, based on carbon balance results, updating paragraph (b)(7)(iv) to require validation of test intervals that were complete prior to a lab equipment or engine malfunction, updating the variable description for w_Cmeas in paragraph (b)(8) to make clear that you may not account for the contribution to α, β, γ, and δ of diesel exhaust fluid or other non-fuel fluids injected into the exhaust, and clarifying regulatory text and correcting paragraph references.
• Section 1036.540—Generally updating to improve the cycle-average engine fuel mapping test procedure as a result of the jointly funded EPA-EMA test program at SwRI. The overall result of these updates is to reduce the variability of the emission test results to reduce lab-to-lab variability. We further modified the proposed language in a few ways by adding paragraph (b)(4) to address the ability of gaseous fueled engines with single point fuel injection to pass alternate cycle statistics to validate the transient duty cycle in 40 CFR part 1037, appendix I, by adding paragraph (e)(2) to describe how EPA will determine the official fuel consumption rate during a confirmatory test, based on carbon balance results, by deleting the requirement for EPA to use an average of indirect measurement of fuel flow with dilute sampling and direct sampling for fuel mapping as EPA will now perform the carbon balance verification in 40 CFR 1065.543, and by generally adding some clarifying text.
• Section 1036.543—Adding a section to address carbon balance error verification. This is a result of the jointly funded EPA-EMA test program. The overall result of these updates is to reduce the variability of the emission test results to reduce lab-to-lab measurement variability.
• Section 1036.801—Adding a definition for hybrid engine to correspond with the addition of the hybrid powertrain test procedures to part 1036. Modifying the definition from the proposed language to provide examples of hybrid engine architecture and hybrid energy storage systems.
• Section 1036.801—Adding definitions for “hybrid powertrain” and “mild hybrid” in the final rule. These definitions are needed as a result of adding hybrid powertrain test procedures to part 1036, subpart F, including mild hybrid certification where engine testing can use a transmission model. The definitions make clear what hybrid architectures are covered by each of these terms.
• Section 1036.801—Updating definition of “steady-state” to clarify that fuel map and idle tests are steady-state tests.
• Section 1036.805(b)—Updating quantity and quantity descriptions, including some changes to those proposed to ensure consistency throughout the part.
• Section 1036.805(c) and (d)—Updating table introductory sentence and column headings in the table to be consistent with format in other parts.
• Section 1036.805(e)—Updating acronyms and abbreviations, including some changes to those proposed to ensure that the table contained all that were used throughout the part.
• Section 1036.805(f)—Adding gravitational constant, including an updated value for the gravitational constant based on consideration of comments received on the proposal.
• Part 1036, appendix A—Adding a new appendix A to provide a historic summary of previous emission standards which EPA originally adopted under 40 CFR part 85 or 86, that apply to compression-ignition engines produced before model year 2007 and to spark-ignition engines produced before model year 2008.
• Part 1036, appendix B(a)—Adding a new paragraph (a) of appendix B to specify transient duty cycles for the engine and powertrain testing described in § 1036.510.
• Part 1036, appendix B(b)—Adding a new paragraph (b) of appendix B to migrate over the spark-ignition FTP duty cycle from part 86, which includes no changes to the FTP duty-cycle weighting factors or the duty-cycle speed values from the current heavy duty diesel engine (HDDE) FTP duty cycle that applies to criteria pollutant regulation in paragraph (f)(1) of 40 CFR part 86, appendix I, a change to the negative torque values, and migration of the HDDE FTP drive schedule to paragraph (b) of 40 CFR part 1036, appendix B, to add vehicle speed and road grade to the duty-cycle to facilitate powertrain testing for compliance with the HD Phase 2 GHG standards. The change to negative torque values is the removal of and footnoting of the negative normalized vehicle torque values over the HDDE FTP duty-cycle. The footnote denotes that these torque points are controlled using closed throttle motoring, which would then match how negative torque values have been controlled in the HDDE FTP. This change also reflects the way that engine manufacturers are already controlling to negative torque from spark-ignition engines and harmonizes the methodology with the HDDE FTP, with no effect on stringency. The spark-ignition engine denormalization equation in 40 CFR 86.1333(a)(1)(ii) includes division by 100 which equates it to the denormalization equation in 40 CFR 1065.610(c)(1) (Equation 1065.610-3), with no effect on stringency. We have further modified the proposed language in this section by updating the road-grade coefficients to reflect additional refinement of the road-grade development process that is described in Section II.A.7 of the preamble.
• Part 1036, appendix B(c)—Adding a new paragraph (c) of 40 CFR part 1036, appendix B, to migrate over the compression-ignition FTP duty cycle from part 86, which includes no changes to the HDDE FTP weighting factors or the duty-cycle torque values from the duty cycle that currently apply to criteria pollutant regulations in paragraph (f)(2) of 40 CFR part 86, appendix I, a change to the speed values that does not influence the ultimate denormalized speed, and migration of the HDDE FTP drive schedule to add vehicle speed and road grade to the duty-cycle to facilitate powertrain testing for compliance with the Phase 2 GHG standards. The change to speed values takes the normalized vehicle speeds over the HDDE FTP duty-cycle and multiplies them by 100/112 to eliminate the need to divide by 112 in the diesel engine denormalization equation in 40 CFR 86.1333(a)(1)(i). This eliminates the need for use of a denormalization equation and allows commonization (between compression- and spark-ignition engines) of the use of the denormalization equation in 40 CFR 1065.610(c)(1) (Equation 1065.610-3), with no effect on stringency. We have further modified the proposed language in this section by updating the road grade coefficients to reflect additional refinement of the road grade development process that is described in Section II.A.7 of the preamble.

2. 40 CFR Part 1037 Test Procedures

EPA proposed several updates to the testing and measurement provisions of 1037 subpart F related to how to measure emissions from heavy-duty vehicles and determine certain GEM inputs and requested comment on general improvements to the vehicle test procedures and compliance provisions (see 85 FR 28142). This section presents the changes we are adopting to vehicle test procedures after consideration of comments received. Chapter 2 of our Response to Comments includes additional details on some of these amendments, as well as other testing and measurement amendments or clarifications requested by commenters and our responses. Amendments for other subparts of part 1037 (i.e., amendments not directly related to test procedures) are discussed in Section II.C.15. We are generally finalizing revisions as proposed; however, some revisions include further changes and clarifications after consideration of public comments to better ensure clarity, accuracy and consistency with the intent of the proposed rule.

• Section 1037.501(i)—Adding paragraph (i) to note that the declared GEM inputs for fuel maps and aerodynamic drag area typically includes compliance margins to account for testing variability; for other measured GEM inputs, the declared values are typically the measured values without adjustment.
• Section 1037.510(a)(2)—Updating the powertrain testing procedure used to generate GEM inputs to reduce the variability of the emission test results and to improve lab-to-lab measurement variability consistent with the results from the jointly funded EPA-EMA test program at SwRI.
• Section 1037.510 Table 1—Updating footnote format in table.
• Section 1037.510(d)—Clarifying the reference to specifically refer to paragraphs “(b) and (c)” of § 1066.425.
• Section 1037.510(e)—Clarifying to specifically state that the use of cruise control is optional.
• Section 1037.515 Table 2—Correcting a table entry to include the proper mathematical symbols in response to a comment by the California Air Resources Board (CARB).
• Section 1037.515 Table 3—Updating footnote format in table.
• Section 1037.520—Updating a reference to reflect the updated version of the GEM model released in conjunction with this rulemaking.
• Section 1037.520(b)(3)(i)—Adding a reference to § 1037.525 to clarify how to determine a high-roof tractor's aerodynamic test results in response to a comment request from EMA.
• Section 1037.520 Table 4—Correcting a typographical error in a tractor aerodynamic test result C_dA value for Bin III low-roof cabs.
• Section 1037.520 Table 5—Correcting a typographical error in a tractor input C_dA value for Bin II High-Roof Sleeper Cabs.
• Section 1037.520(c)—Adding a clarification to § 1037.520(c)(6) and updating the GEM user guide to clarify that a time- and load-weighted average be applied to calculate the rolling resistance of tires installed on liftable axles, given that tires on liftable axles are only in contact with the ground when the axle is in a deployed state in response to a comment from EMA.
• Section 1037.520 Table 6—Updating footnote format in table.
• Section 1037.520 Table 7—Clarifying that the nonwheel-related weight reductions from alternative materials applied to tractors for non-suspension crossmembers is for a set of three.
• Section 1037.520 Table 8—Adding two footnotes to address how weight reduction values apply and what values to use for medium heavy-duty vehicles (Medium HDV) with 6x4 or 6x2 axle configurations. Also see Section II.C.3.
• Section 1037.520(f)—Updating a cross-reference.
• Section 1037.520(g)—Adding and clarifying which vehicle characteristics need to be reported, including providing a better description in paragraph (g)(2)(iv) of the 6x4D drive axle configuration as well as qualifying conditions for use of this configuration. After considering comments received by Allison and Ford, we are further modifying this paragraph by noting in paragraph (g)(1), and similarly in § 1037.231(b)(7), that available forward gear means the vehicle has the hardware and software to allow operation in those gears and providing in paragraph (g)(2)(i) that the 4x2 drive axle configuration is available to vehicles with two drive axles where one of them is disconnectable and designed to be connected only when used in off road or slippery road conditions and based on a qualifying condition.
• Section 1037.520(h)—Adding provisions to determine appropriate vehicle idle speed based on vehicle service class and applicable engine standard, including in the final rule a clarification that the 750 rpm value applies to Light HDV and Medium HDV vocational vehicles and providing an idle speed value of 700 rpm for Medium HDV tractors, corresponding to the idle speed used to set the standards for those vehicles, in response to a comment from EMA. These final provisions incorporated in a new table format, with an updated footnote noting the appropriate adjustable idle speed to choose if an engine cannot operate at the idle speed specified in the table.
• Section 1037.520(i)—Adding that a manufacturer can characterize a torque converter, in addition to an axle and transmission, which will improve the accuracy of GEM by replacing default GEM values with more representative values.
• Section 1037.520(j)(2)—Removing a superfluous reference to tractors in paragraph (j)(2)(i); clarifying paragraph (j)(2)(iii) in response to a comment from EMA to indicate how to demonstrate the performance of high-efficiency air conditioning compressors.
• Section 1037.520(j)(4) Table 9—Including additional combinations of idle reduction technologies and their corresponding GEM input values.
• Section 1037.520(j)(5)—Correcting typographical error that transposed school and coach bus GEM inputs.
• Section 1037.525—See Section II.A.6 for a description of comments and final revisions to this section.
• Section 1037.528—Replacing the phrase “primary procedures” with “reference method” for tractors and “alternate procedures” with “an alternate method” for trailers to maintain consistency with terminology used throughout subpart F.
• Section 1037.528(c)—Clarifying that the conditions listed in paragraph (c) apply to each run separately.
• Section 1037.528(e)—Removing requirement that the anemometer be “electro-mechanical” to rely instead on the specifications outlined in the existing reference to SAE J1263.
• Section 1037.528(g)(3)—Clarifying that the measured air direction correction is “from all the high-speed segments.”
• Section 1037.528(h)(3)(i)—Clarifying how to account for measurement noise near the 2 mile/hour boundary.
• Section 1037.528(h)(6)—Adding a definition of D F_TRR to the introduction of paragraph (h)(6) to clarify the required calculations; relocating the proposed direction to determine the difference in rolling resistance between 65 mph and 15 mph for each tire and to use good engineering judgment when measuring multiple results to paragraph (v) with the corresponding D F_TRR equation.
• Section 1037.528—Updating equation 11 and the corresponding example to include the appropriate variable to represent inflation pressure variable with a lowercase “p”.
• Section 1037.528—Updating equation 13 to include appropriate units for the ambient temperature variable.
• Section 1037.528—Updating equation 14 to replace a “+” with a “−” to correct a typographical error.
• Section 1037.528(h)(12)—Updating a variable name to provide consistency with updates made to § 1037.525.
• Section 1037.532—See Section II.A.6 for a description of comments and final revisions to this section.
• Section 1037.534—Updating equation 6 and the corresponding example to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1037.540—Updating equations 1, 2, and 3 to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1037.540 Table 1—Updating footnote format in table; updating a parameter name.
• Section 1037.540(e) and (f)—Removing incorrect cross-reference to § 1036.540(d)(5); adding reference to definition of standard payload.
• Section 1037.550—Updating the powertrain testing procedure to reduce the variability of the emission test results and improve lab-to-lab variability consistent with the results from the jointly funded EPA-EMA test program at SwRI. We further modified this section to include an introduction paragraph and reorganized paragraphs with new paragraph headings to improve navigation. Additional modifications to this section in the final rule include clarifying in paragraph (a)(3) options available to create the models for powertrain testing, adding clarifications in several paragraphs to address where the torque and speed are measured based on powertrain setup, adding a new paragraph (f)(2) to address testing of hybrid engines using the transmission model in GEM, modifying paragraph (b) to give additional clarification on how to set the engine idle speed, adding a new paragraph (f)(2) for testing with torque measurement at the engine's crankshaft and how to calculate the transmission output rotational speed, updating paragraph (j)(2) to describe how to transition between duty cycles if the preceding cycle ends at 0 mi/hr, adding a new paragraph (j)(5) to describe how to warm up the powertrain, adding a new paragraph (o)(2) to describe how EPA will determine the official fuel consumption rate during a confirmatory test, based on carbon balance results, and updating paragraphs (o)(3) through (5) to better define when a vehicle is not moving, moving the text from paragraph (p) into paragraph (o)(1), moving the text of paragraph (q) to the general provisions as a new paragraph (a)(5). The final rule includes additional revisions regulatory text to provide greater clarity and more carefully describe the procedures.
• Section 1037.551(b)—Updating a reference.
• Section 1037.555—Updating equations 1 and 3 to include the appropriate variable to represent increments by italicizing the “i”; updating a parameter name in Table 1 for consistency in this part.
• Section 1037.560—Clarifying that it is optional to drain gear oil after the break in period is complete, providing the option of an alternative temperature range to provide international harmonization of testing, editing the P_loss (i.e., power loss) variable description to improve the readability, and adding paragraph (h) to describe how to derive axle power loss maps for untested configurations in a family. We further modified this section in the final rule by clarifying in paragraph (a) that for tandem axles that can be disconnected, testing both single-drive and tandem axle configurations includes 4x4 axles where one of the axles is disconnectable; adding a new paragraph (h)(4) and modifying (h)(5) to address comments regarding results when multiple gear ratios are tested and one of the points is above the linear regression line, which could cause the regression values to understate power loss, to clarify that you must add the difference between the datapoint and the regression line to the intercept values of the regression line to mitigate this effect; and updating the use of the term “axle” to “axle assembly” throughout the section to provide consistency.
• Section 1037.565—Providing an option to map additional test points to provide international harmonization of testing, including edits to improve the readability of the P_loss variable description, and adding paragraph (d)(4) and clarifying paragraphs (e)(6) and (7) regarding the gears the transmission is tested in. After considering comments from Allison, EMA, and Eaton Cummins Automated Transmission Technologies, we further modified this section by: Updating the torque transducer accuracy requirements in paragraph (c) to link it to the highest transmission input torque or respective output torque; adding additional detail in paragraph (d)(1) on the maximum transmission input shaft speed to test, specifically the maximum rated input shaft speed of the transmission or the maximum test speed of the highest speed engine paired with the transmission. and the minimum idle speed to test, specifically 600 r/min or the minimum idle speed of the engines paired with the transmission; modifying paragraph (d)(2) in response to comments regarding transmission torque setpoints to optionally allow, in higher gear ratios where output torque may exceed dynamometer torque limits, the use of good engineering judgment to measure loaded test points at input torque values lower than specified (in this case GEM may need to extrapolate values outside of the measured map, however extrapolation time may not exceed 10% for any given cycle and you must describe in the application for certification how you adjusted the torque setpoints); modifying paragraph (e)(9) to allow the use of the maximum loss value achieved from all the repeats of the test points to calculate transmission efficiency if you cannot meet the repeatability requirements; adding a new paragraph (e)(11) clarifying what needs to be calculated for each point in the test matrix; modifying paragraph (g) and moving part of existing paragraph (g) to a new paragraph (h) to avoid a potentially never-ending cycle of repeat testing if repeatability requirements are not achieved. If the repeatability requirement is not met after conducting three or more tests, the maximum loss value may be used to calculate transmission efficiency, or you can continue to test until you pass the repeatability requirement.
• Section 1037.570—Adding new section to characterize torque converters to allow a manufacturer to determine their own torque converter capacity factor instead of using the default value provided in GEM. The option to use the default value remains. The final rule includes updated regulatory text to provide greater clarity and more carefully describe the procedures. Final revisions do not change the proposed procedure; instead, they include updates to revise the section heading, reorganize paragraphs, ensure consistent terminology, and clarify measurement points.

3. 40 CFR Part 1065 Test Procedures

EPA proposed several updates to the testing and measurement provisions of 40 CFR part 1065 related to how to measure emissions from heavy-duty highway and nonroad engines and requested comment on general improvements to the engine test procedures and compliance provisions (see 85 FR 28142). This section presents the changes we are adopting primarily to reduce variability associated with engine test procedures after consideration of comments received. Chapter 2 of our Response to Comments includes additional details on some of these amendments, as well as other testing and measurement amendments or clarifications requested by commenters and our responses.

The regulations in part 1065 rely heavily on acronyms and abbreviations (see 40 CFR 1065.1005 for a complete list). Acronyms used here are summarized in Table II-1:

We are generally finalizing revisions as proposed; however, some revisions include further changes and clarifications after consideration of public comments to better ensure clarity, accuracy and consistency with the intent of the proposed rule.

• Section 1065.1(g)—Updating the test procedure Uniform Resource Locator (URL).
• Section 1065.2(c)—Correcting a typographical error by replacing “engines” with “engine”.
• Section 1065.130(e)—Revising to denote that a carbon balance procedure should be performed to verify exhaust system integrity in place of a chemical balance procedure.
• Section 1065.140(c)(6)(i)—Correcting a typographical error by replacing “dew point” with “dewpoint”.
• Section 1065.140(e)(2)—Clarifying how to determine the minimum dilution ratio for discrete mode testing.
• Section 1065.145(e)(3)(i)—Removing the requirement to heat a sample pump if it is located upstream of a NO_X converter or chiller and replacing it with a requirement to design the sample system to prevent aqueous condensation to better address concerns with the loss of NO₂ in the sampling system where methods other than heating the pump can be used to prevent condensation.
• Section 1065.170—Updating to allow you to stop sampling during hybrid tests when the engine is off and allow exclusion of the sampling off portions of the test from the proportional sampling verification, and adding a provision for hybrid testing to allow supplemental dilution air to be added to the bag in the event that sampled volumes are too low for emission analysis.
• Section 1065.205 introductory and Table 1—Revising and adding recommended performance specifications for fuel and DEF mass scales and flow meters to reduce fuel flow measurement error.
• Section 1065.220(a) introductory and (a)(3)—Updating the application of fuel flow meters to more correctly reflect how and what they are used for in part 1065.
• Section 1065.225(a) introductory and (a)(3)—Updating the application of intake flow meters to more correctly reflect how and what they are used for in part 1065.
• Section 1065.247—Revising to add acronym for DEF throughout in place of “diesel exhaust fluid” and in paragraph (c)(2) account for any fluid that bypasses or returns from the dosing unit to the fluid storage tank.
• Section 1065.260(e)—Adding the word “some” as a qualifier for gaseous fueled engines with respect to using the additive method for NMHC determination.
• Section 1065.266(a) and (b)—Adding flexible fuel engines under the allowance to use Fourier transform infrared (FTIR) and updating the URL for EPA method 320.
• Section 1065.275—Deleting the URL and replacing with a reference to § 1065.266(b).
• Section 1065.280(a)—Updating to reflect that there is no method in § 1065.650 for determining oxygen balance and that you may develop a method using good engineering judgment.
• Section 1065.303 Table 1—Updating the formatting and entries in the summary table to reflect revised requirements, including adding fuel mass scale and DEF mass scale to the linearity verifications in § 1065.307, updating the verification in § 1065.341 to replace “batch sampler” with “PFD” as partial-flow dilution (PFD) is the preferred language, updating one footnote to include the PFD flow verification (propane check) as not being required for measurement systems that are verified by a carbon balance error verification as described in § 1065.341(h) and adding two footnotes excluding linearity verification for DEF flow if the ECM is used and for intake air, dilution air, diluted exhaust, batch sampler, and raw exhaust flow rates flow if propane checks or carbon balance is performed. These are not new exemptions; they are simply relocated to the footnotes.
• Section 1065.307(c)(13)—Adding a clarification that the calculation used for arithmetic mean determination in § 1065.602 uses a floating intercept.
• Section 1065.307(d)(4)—Revising to include DEF mass flow rate and to correct or account for buoyancy effects and flow disturbances to improve the flow measurement.
• Section 1065.307(d)(6)(i)—Revising to state that the span gas can only contain one single constituent in balance air (or N₂ if using a gas analyzer) as the reference signal for linearity determination.
• Section 1065.307(d)(7)—Revising to state that the span gas can only contain one single constituent in balance air (or N₂ if using a gas analyzer) as the reference signal for linearity determination.
• Section 1065.307(d)(9)—Expanding the paragraph to include fuel and DEF mass scales and requirements for performing the linearity verification on these scales.
• Section 1065.307(e)(3)(i) and (ii)—Editing to clarify the intent of the requirements.
• Section 1065.307(e)(3)(iii) through (xi)—Defining maximum flowrate for fuel and DEF mass scales and flow meters as well as maximum molar flowrate for intake air and exhaust flow meters and defining maximum for electrical power, current, and voltage measurement.
• Section 1065.307(e)(5)—Providing additional information surrounding requirements for using a propane check or carbon balance verification in place of a flow meter linearity verification.
• Section 1065.307(e)(7)(i)(F) and (G)—Adding transmission oil and axle gear oil to temperature measurements that require linearity verification.
• Section 1065.307(f)—Adding new paragraph (f) to denote that table 1 follows.
• Section 1065.307 Table 1—Adding DEF flow rate, fuel mass scale, and DEF mass scale to measurement systems and updating the footnote format.
• Section 1065.307(g)—Adding a new paragraph (g) to denote that table 2 follows.
• Section 1065.307 Table 2—Adding a new Table 2 to provided additional guidance on when optional verifications to the flow meter linearity verifications can be used.
• Section 1065.309(d)(2)—Updating to allow the use of water vapor injection for humidification of gases. After considering comments from EMA and Auto Innovators, we further modified this section to make language consistent where water vapor injection was added as an alternative.
• Section 1065.320(b)—Deleting existing paragraph (b) and marking it “reserved” as this is now adequately covered in § 1065.307.
• Section 1065.341—Revising section heading, adding introductory text, revising paragraph (a) to clarify which subparagraphs apply to CVS and which apply to PFD, relocating some of existing paragraph (a) to paragraph (f) and reordering existing paragraphs (b) through (f) as paragraphs (a) through (e).
• Section 1065.341(g)—Revising to replace “batch sampler” with “PFD” throughout and editing to provide further clarification on the procedure.
• Section 1065.341(h)—Adding a new paragraph to reference Table 2 of § 1065.307 regarding when alternate verifications can be used.
• Section 1065.342(d)(2)—Updating to allow the use of water vapor injection for humidification of gases. After considering comments by EMA and Auto Innovators, we further modified this section to make language consistent where water vapor injection was added as an alternative.
• Section 1065.350(d)(2)—Updating to allow the use of water vapor injection for humidification of gases. After considering comments by EMA and Auto Innovators, we further modified this section to make language consistent where water vapor injection was added as an alternative.
• Section 1065.355(d)(2)—Updating to allow the use of water vapor injection for humidification of gases. After considering comments by EMA and Auto Innovators, we further modified this section to make language consistent where water vapor injection was added as an alternative.
• Section 1065.360(a)(4)—Adding a new option to determine methane and ethane THC FID response factors as a function of exhaust molar water content when measuring emissions from a gaseous fueled engine. This is to account for the effect water has on non-methane cutters. We received a comment regarding whether the new regulatory text for the allowance is optional. The intent is that if you decide to use the option to determine the methane and ethane THC FID response factors as a function of exhaust molar water content, you must generate and verify the humidity as described in § 1065.365(d)(12). Paragraph (a)(4) has been modified to make this clear.
• Section 1065.360(d)(12)—Adding a process to determine methane and ethane THC FID response factors as a function of exhaust molar water content when measuring emissions from a gaseous fueled engine. This is to account for the effect water has on non-methane cutters.
• Section 1065.365(a)—Removing chemical symbol for methane in parenthetical.
• Section 1065.365(d)—Adding a requirement to determine NMC FID methane penetration fraction and ethane response factor as a function of exhaust molar water content when measuring emissions from a gaseous fueled engine. This is to account for the effect water has on non-methane cutters.
• Section 1065.365(d)(9)—Adding C₂ H₆ before “response factor” and “penetration fraction” to clarify, as intended, that these are the ethane response factor and ethane penetration fraction.
• Section 1065.365(d)(10), (11), and (12)—Adding a process to determine NMC FID methane penetration fraction and ethane response factors as a function of exhaust molar water content when measuring emissions from a gaseous fueled engine. This is to account for the effect water has on non-methane cutters.
• Section 1065.365(f)(9) and (14)—Adding C₂ H₆ before “response factor” and “penetration fraction” to clarify, as intended, that these are the ethane response factor and ethane penetration fraction. Adding CH₄ before “penetration fraction” to clarify, as intended, that this is the methane penetration fraction.
• Section 1065.370(e)(5)—Updating to allow the use of water vapor injection for humidification of gases. After considering comments by EMA and Auto Innovators, we further modified this section to make language consistent where water vapor injection was added as an alternative.
• Section 1065.375(d)(2)—Updating to allow the use of water vapor injection for humidification of gases. After considering comments by EMA and Auto Innovators, we further modified this section to make language consistent where water vapor injection was added as an alternative.
• Section 1065.410(c)—Replacing “bad engine” with “malfunctioning” in relation to engine components after considering a comment by Auto Innovators.
• Section 1065.410(d)—Updating to state that you may repair a test engine if the parts are unrelated to emissions without prior approval. If the part may affect emissions, prior approval is required.
• Section 1065.510(a), (b)(5)(i), (c)(5), and (f)(4)(i)—Moving provision for engine stabilization during mapping from § 1065.510(a) to § 1065.510(b)(5)(i), which lays out the mapping procedure, adding allowance in § 1065.510(f)(4)(i) to specify curb idle transmission torque (CITT) as a function of idle speed in cases where an engine has an adjustable warm idle or enhanced idle. We further modified this section in the final rule by adding a provision in § 1065.510(c)(5) for hybrid powertrain testing to map negative torque required to motor the engine with the RESS fully charged.
• Section 1065.512(b)(1) and (2)—Updating procedures on how to operate the engine and validate the duty-cycle when an engine utilizes enhanced-idle speed. This also addresses denormalization of the reference torque when enhanced-idle speed is active.
• Section 1065.514(e)—Clarifying that a floating intercept as described in § 1065.602 is used to calculate the regression statistics to harmonize with changes made to § 1065.602 and further modifying paragraph (e)(3) in the final rule to change “standard estimates of errors” to “standard error of the estimate” for consistency with other parts.
• Section 1065.514 Table 1—Updating a parameter name in the final rule for consistency with other parts.
• Section 1065.530(a)(2)(iii)—Adding instructions on how to determine that the engine temperature has stabilized for air cooled engines.
• Section 1065.530(g)(5)—Adding a new paragraph on carbon balance error verification if it is performed as part of the test sequence.
• Section 1065.543—Adding a new section on carbon balance error verification procedure to further reduce measurement variability for the fuel mapping test procedure in part 1036. We have further modified this section in the final rule to make it optional to account for the flow of other non-fuel carbon-carrying fluids into the system as the overall contribution from any such fluids to the total carbon in the system is negligible.
• Section 1065.545—Revising to clarify that a forcing the intercept through zero as described in § 1065.602 is used to calculate the standard error of the estimate (SEE) to harmonize with changes to § 1065.602.
• Section 1065.602(b), (c), (d), (e), (f), (g), (h), (j), (k)—Updating to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1065.602 Table 1—Updating footnote format in table.
• Section 1065.602 Table 2—Correcting a typographical error where the N_ref-1 value should be “22” but was mistakenly listed as “20”.
• Section 1065.602(h)—Defining the existing Equation 1065.602-9 as a least squares regression slope calculation where the intercept floats, i.e., is not forced through zero, designating this paragraph as (h)(1) and adding a new paragraph (h)(2) for Equation 1065-602-10, a least squares regression slope calculation where the intercept is forced through zero.
• Section 1065.602(i)—Editing to state that the intercept calculation Equation 1065.602-11 is for a floating intercept.
• Section 1065.602(j)—Defining the existing Equation 1065.602-12 (renumbered from 1065.602-11) as a SEE calculation where the intercept floats, i.e., is not forced through zero, designating this paragraph as (j)(1), adding a new paragraph (j)(2) for Equation 1065.602-13, a SEE calculation where the intercept is forced through zero, and further modifying paragraph (j) in the final rule to change “Standard estimate of error” to “Standard error of the estimate” for consistency with other parts.
• Section 1065.610(a)(1)(iv)—Updating to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1065.610(a)(2)—Clarifying that the alternate maximum test speed determined is for all duty-cycles.
• Section 1065.610(d)(3)—Adding provision to use good engineering judgment to develop an alternate procedure for adjusting CITT as a function of speed.
• Section 1065.640(a), (b)(3), and (d)(1)—Deleting a comma in paragraph (a), specifying that the least square regression calculation in paragraph (b)(3) is with a floating intercept, providing a conversion to kg/mol for M_mix in the example problem for paragraph (d)(1), and correcting an error in the example problem in applying Equation 1065.640-10 where M_mix was used with the wrong units.
• Section 1065.640(d)(3)—Providing additional guidance on how to calculate SEE for C_d to correspond with the changes made to § 1065.602.
• Section 1065.642(b)—Correcting a cross-reference.
• Section 1065.642(c)(1)—Defining C_f.
• Section 1065.643—Adding a new section on carbon balance error verification calculations to support the new § 1065.543.
• Section 1065.650(b)(3)—Adding DEF to clarify what is needed for chemical balance calculations.
• Section 1065.650(c)(1)—Relocating transformation time requirement from § 1065.650(c)(2)(i) to § 1065.650(c)(1).
• Section 1065.650(c)(3)—Updating the equation to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1065.650(d)—Correcting cross-references.
• Section 1065.650(d)(7)—Updating to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1065.650(f)(2)—Adding DEF to clarify what is needed for chemical balance calculations.
• Section 1065.650(g)—Updating the equations to include the appropriate variable to represent increments by italicizing the “i” and correcting variable name from e_NOxcomposite to e_NOxcomp.
• Section 1065.655—Adding “DEF” to the section heading.
• Section 1065.655(a) and (c) introductory text—After considering comments by EMA, we modified this section to clarify that the inclusion of diesel exhaust fluid in the chemical balance is optional.
• Section 1065.655(c)(3)—Updating the x_Ccombdry variable description to include injected fluid.
• Section 1065.655(d)—After considering comments by EMA, we modified this section to clarify that the inclusion of diesel exhaust fluid in the wC determination is optional.
• Section 1065.655(e)(1)(i)—Clarifying the determination of carbon and hydrogen mass fraction of fuel, specifically to S and N content.
• Section 1065.655(e)(3)—Clarifying that nonconstant fuel mixtures also applies to flexible fueled engines.
• Section 1065.655(e)(4)—Updating to include the appropriate variable to represent increments by italicizing the “i”.
• Section 1065.655(e)(5)—Adding new paragraph (e)(5) to denote that table 1 follows.
• Section 1065.655 Table 1—Updating cross-reference.
• Section 1065.655(f)(3)—Restricting the use of Equation 1065.655-25 if the standard setting part requires carbon balance verification and including the appropriate variable to represent increments by italicizing the “j”; adding in the final rule a description of the variable for carbon mass fraction, as it was missing.
• Section 1065.655(g)(1)—Updating cross-reference.
• Section 1065.659(c)(2) and (3)—Adding DEF to clarify what is needed for chemical balance chemical balance calculations.
• Section 1065.660(a)(5) and (6)—Adding new paragraphs to those proposed codifying existing practice to calculate THC based on measurements made with FTIR for gaseous fueled engines. EPA intended in previous updates to part 1065 to allow the determination of NMNEHC and NMHC using FTIR from gaseous fueled engines, but the HD Phase 2 rulemaking inadvertently omitted instructional text in paragraph (a) on calculating THC using the two FTIR additive methods.
• Section 1065.660(b)(2) and (3)—Correcting typographical errors, including adding missing commas.
• Section 1065.660(b)(4)—Correcting a typographical error for the chemical formula of acetaldehyde in a variable.
• Section 1065.660(c)(2)—Including NMC FID as allowable option in NMNEHC calculation and further modifying § 1065.660(c) in the final rule adding additional information on performing the NMNEHC calculation and to correct typos in variables.
• Section 1065.660(d)—Adding missing parentheses.
• Section 1065.665(a)—Deleting the variable and description for C# as it is not used in any calculation in this section.
• Section 1065.667(d)—Adding DEF to clarify what is needed for chemical balance description.
• Section 1065.675(d)—Editing variable descriptions to refer to a humidity generator rather than a bubbler (accommodates both a bubbler and humidity generator).
• Section 1065.695(c)(8)(v)—Adding carbon balance verification.
• Section 1065.701(b)—Updating name of California gasoline type.
• Section 1065.701 Table 1—Updating footnote format in table.
• Section 1065.703 Table 1—Updating to correct units for kinematic viscosity and updating footnote format in table.
• Section 1065.705 Table 1—Updating to correct units for kinematic viscosity and updating footnote format in table.
• Section 1065.710 Table 1—Editing format for consistency and updating footnote format in table.
• Section 1065.710 Table 2—Editing format for consistency, adding allowance to use ASTM D1319 or D5769 for total aromatic content determination and ASTM D1319 or D6550 for olefin determination because the dye used in ASTM D1319 is becoming scarce and an alternate method is needed, and updating a footnote format in table.
• Section 1065.715 Table 1—Updating footnote format in table.
• Section 1065.720 Table 1—Updating footnote format in table and revising Table 1 after considering a comment by EMA to specify ASTM D6667 instead of ASTM D2784 as the reference procedure for measuring sulfur in liquefied petroleum gas. We requested comment on amending the regulation to replace ASTM D2784, which has been withdrawn by ASTM without replacement, received comment from EMA and agree that ASTM D6667 is a suitable method. EPA is similarly changing other regulatory provisions to specify ASTM D6667 as the reference procedure for fuel manufacturers measuring sulfur in butane (see 40 CFR 1090.1350).
• Section 1065.750 Table 1—Updating footnote format in table.
• Section 1065.790(b)—Adding a NIST traceability requirement for calibration weights for dynamometer, fuel mass scale, and DEF mass scale.
• Section 1065.905 Table 1—Updating footnote format in table.
• Section 1065.910(a)(2)—Adding a revision in the final rule to change the requirement to use 300 series stainless steel tubing to connect the PEMS exhaust and/or intake air flow meters into a recommendation because there are other materials that are equally suitable for in-use testing other than stainless steel tubing.
• Section 1065.915 Table 1—Updating footnote format in table.
• Section 1065.1001—Adding a definition for enhanced-idle.
• Section 1065.1001—Clarifying definition of test interval as duration of time over which the mass of emissions is determined.
• Section 1065.1005(a)—Updating footnote format in table and parameter names for consistency with other parts.
• Section 1065.1005(c), (d), and (e)—Updating to ensure column headings use terminology consistent with NIST SP-811.
• Section 1065.1005(a) and (e)—Updating tables of symbols and subscripts to reflect revisions to part 1065.
• Section 1065.1005(f)(2)—Adding molar mass of ethane and updating footnote format in table.
• Section 1065.1005(g)—Updating acronyms and abbreviations for ASTM, e.g., and i.e.
• Section 1065.1010(b)(23) and (43)—Incorporating by reference ASTM D6667 into the regulations instead of ASTM D2784, consistent with replacing ASTM D2784 with ASTM D6667 as the reference procedure for measuring sulfur in liquefied petroleum gas in § 1065.720, as explained above in this section. EPA is similarly specifying ASTM D6667 as the reference procedure for fuel manufacturers measuring sulfur in butane.

4. 40 CFR Part 1066 Test Procedures

EPA proposed several updates to the testing and measurement provisions of 40 CFR part 1066 related to how to measure emissions from light- and heavy-duty vehicles and requested comment on general improvements to the vehicle test procedures and compliance provisions (see 85 FR 28144). This section presents the changes we are adopting to vehicle test procedures after consideration of comments received. Chapter 2 of our Response to Comments includes additional details on some of these amendments, as well as other testing and measurement amendments or clarifications requested by commenters and our responses.

We are generally finalizing revisions as proposed; however, some revisions include further changes and clarifications after consideration of public comments to better ensure clarity, accuracy and consistency with the intent of the proposed rule.

• Section 1066.1(g)—Updating the URL.
• Section 1066.135(a)(1)—Revising to widen the range for verifications of a gas divider derived analyzer calibration curve to 10 to 60% to ease lab burden with respect to the number of gas cylinders they must have on hand and revising to make the midspan check optional as the part 1066 requirement for yearly linearity verification of the gas divider has provided more certainty of the accuracy of the gas blending device.
• Section 1066.210(d)(3)—Changing the value for acceleration of Earth's gravity from a calculation under 40 CFR 1065.630 to a default value of 9.80665 m/s² because the track coastdown doesn't take place in the same location that the dynamometer resides. Therefore, best practice is to use a default value for gravity.
• Section 1066.255(c)—Clarifying that the torque transducer zero and span are mathematically done prior to the start of the procedure.
• Section 1066.260(c)(4)—Correcting an error in the example problem result.
• Section 1066.265(d)(1)—Correcting example equation to replace a subtraction sign that was a typographical error with a multiplication sign.
• Section 1066.270(c)(4)—Correcting units for force in mean force variable description and correcting example problem solution.
• Section 1066.270(d)(2)—Adding corrections in the final rule of typographical errors on maximum allowable error where error tolerances were indicated as “±”, but paragraph is clear that the allowable error is a maximum value as Equation 1066.270-2 determines error as an absolute value. Therefore, the error values are positive and not a positive and negative range.
• Section 1066.275—Extending the dynamometer readiness verification interval from within 1 day before testing to an optional 7 days prior to testing if historic data from the test site supports an interval of more than 1 day. Adding corrections in the final rule of typographical errors in paragraphs (d)(1) and (2) on allowable error where error tolerances were indicated as “±”, but paragraph is clear that the allowable error is a maximum value as Equation 1066.270-2 determines error as an absolute value. Therefore, the error values are positive and not a positive and negative range.
• Section 1066.405—Updating heading to include “maintenance”.
• Section 1066.405(a) through (c)—Designating existing text as paragraph (a), adding new paragraphs (b) and (c) to address test vehicle inspection, maintenance and repair, consistent with § 1065.410, and, after considering a comment by Auto Innovators, replacing “bad engine” with “malfunctioning” in relation to engine components in paragraph (b).
• Section 1066.420 Table 1—Updating footnote format in table and, after considering comments from Auto Innovators and VW, clarifying that SC03 humidity tolerance is an “average” value consistent with 40 CFR 86.161-00(b)(1) and inadvertently not carried over in part 1066. All SC03 capable test cells have been designed to meet the humidity requirement in § 86.161-00 which is on an average basis.
• Section 1066.605—Correcting a typographical error in paragraph (c)(4) where NMHC should read NMHCE and editing Equation 1066.605-10 adding italics for format consistency.
• Section 1066.610—Editing Equation 1066.610-4 adding italics for format consistency.
• Section 1066.710(c)—Clarifying to reflect how heating, ventilating, and air conditioning (HVAC) control systems operate in vehicles and how they should be operated for the test. Further modifying paragraph (c)(1)(i)(A) in the final rule to state that for automatic temperature control systems that allow the operator to select a specific temperature, set the air temperature at 72 °F or higher, which the vehicle then maintains by providing air at that selected constant temperature. Further modifying paragraph (c)(2) in the final rule to state that for full automatic temperature control systems that allow the operator to select a specific temperature, set the air temperature at 72 °F, which the vehicle then maintains by varying temperature, direction and speed of air flow. Clarifying terminology is consistent with EPA compliance guidance CD-2020-04.
• Section 1066.801 Figure 1—Updating to reflect that the initial vehicle soak, as outlined in the regulations, is a 6-hour minimum and not a range of 6 to 36 hours.
• Section 1066.835(a)—Clarifying that the last drain and fill operation is after the most recent FTP or highway fuel economy test (HFET) measurement (with or without evaporative emission measurements).
• Section 1066.835(f)(2)—Deleting the word “instantaneous” to reflect that the SC03 temperature and humidity tolerances in paragraph (f)(1) are not all instantaneous in response to comments received from Auto Innovators and Volkswagen. This was an inadvertent error in part 1066.
• Section 1066.930—Adding a period to the end of the sentence.
• Section 1066.1005(a)—Updating a parameter name to be consistent with use in other parts.
• Section 1066.1005(c) and (d)—Updating to ensure column headings use terminology consistent with NIST SP-811.
• Section 1066.1005(f)—Updating footnote format in table.

5. Greenhouse Gas Emissions Model (GEM)

EPA proposed several updates to the GEM model related to how to measure emissions from heavy-duty engines and requested comment on whether the differences in GEM would impact the effective stringency of the standards and, if so, whether either GEM or the regulations need to be revised to address the changes (see 85 FR 28145, May 12, 21020). This section presents the changes we are adopting to GEM after consideration of comments received. Additional details on these and other amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments.

GEM is a computer application that estimates the greenhouse gas (GHG) emissions and fuel efficiency performance of specific aspects of heavy-duty (HD) vehicles. GEM is used to determine compliance with the Phase 2 standards from several vehicle-specific inputs, such as engine fuel maps, aerodynamic drag coefficients, and vehicle weight rating. GEM simulates engine operation over two cruise cycles, one transient cycle, and for vocational vehicles, idle operation. These results are weighted by GEM to provide a composite GEM score that is compared to the standard.

EPA proposed to update GEM, in a revised version 3.5 to replace the current version 3.0, and requested comment on whether the differences in GEM would impact the effective stringency of the standards and, if so, whether either GEM or the regulations need to be revised to address the changes. We received one comment on the proposal on this topic from the California Air Resources Board (CARB), stating the importance of GEM results being consistent with the current program standards to ensure stringency is maintained and recommending that EPA revise GEM to maintain this consistency.

After considering the comment and further evaluating the performance of GEM 3.5 with the input files used to set the Phase 2 vehicle standards, EPA is finalizing GEM version 3.5.1 applicable for MY 2021 vehicles that includes the changes proposed in version 3.5 as well as changes that correct three errors in the GEM 3.5 code. The following changes were proposed in version 3.5 and are finalized in version 3.5.1 to allow additional compliance flexibilities and improve the vehicle simulation:

• Corrected how idle emission rates are used in the model.
• Increased the allowable weight reduction range to 25,000 pounds.
• For powertrain input, added an input for powertrain rated power to scale default engine power.
• Recalibrated driver over speed allowance on cruise cycles from 3 mph to 2.5 mph.
• Revised engine cycle generation outputs with corrected engine cycle generation torque output from model based on simulated inertia and rate limited speed target.
• Added scaling of powertrain simulation default engine and transmission maps based on new rated power input.
• Changed interpolation of fuel map used in post processing to be consistent with one used in simulation.
• Corrected accessory load value on powertrain test when coasting or decelerating.
• Added torque converter k-factor input option.
• Cycle average cycles: added flag for points that are to be considered “idle.”
• Improved handling of large input tables.
• Allow hybrid engine input.

The three additional changes in GEM 3.5.1 correct the following errors in GEM 3.5 code: (1) A typographical error, where GEM used a weighting factor of 0.25 instead of 0.23 for the Heavy Heavy-Duty (HHD) Multipurpose vehicle subcategory; (2) an idle map error when the cycle average fuel mapping procedure is used for all three drive cycles; and (3) a functional error that unnecessarily required transmission power loss data when using the option to enter a unique (instead of default) k-factor for the torque converter. The GEM version we are releasing with and incorporating by reference in this final rule is identified as “3.5.1.”

EPA is also issuing a supplemental proposal published in the Proposed Rules section of this issue of the Federal Register, titled “Improvements for Heavy-Duty Engine and Vehicle Test Procedures,” docket number EPA-HQ-OAR-2019-0307; FRL-10018-51-OAR. This supplemental proposal provides notice and opportunity for comment on a proposed further updated version of GEM for MY 2022 and later, proposes to allow use of the updated model for MY 2021 for demonstrating compliance with the Phase 2 standards, including obtaining a certificate of conformity and submitting end-of-year reports, and requests comment on whether this version of GEM should be required for MY2021 end-of-year reports. This proposed revised version in the supplemental proposal includes corrections, clarifications, additional flexibilities, and adjustment factors to the Greenhouse gas Emissions Model (GEM) compliance tool for heavy-duty vehicles after consideration of comments received on the proposed rule. The supplemental proposal proposes limiting the use of GEM 3.5.1 to MY 2021 vehicles only, except where this MY 2021 data can be used for carryover requests for certificates of conformity for MY 2022 and future years for qualifying vehicles under § 1036.235(d); however, manufacturers would still need to use GEM 3.8 for end-of-year reporting for MY 2022 and future years.

EPA is finalizing GEM 3.5.1 after considering comments, further evaluating the performance of GEM 3.5.1 with the input files used to set the Phase 2 vehicle standards, considering the corrections and improvements made in GEM 3.5.1, and identifying potential additional corrections and improvements for GEM. Evaluation of GEM 3.5.1 indicated that there was some difference in output 96results for both tractor and vocational vehicles when compared to GEM 3.0. To assess the magnitude of any differences between using GEM 3.0 and GEM 3.5.1, we repeated the process used in 2016 to calculate the numerical level of the vehicle standards, replacing GEM 3.0 with GEM 3.5.1. On average, the differences in the resulting standards from using GEM 3.5.1 instead of GEM 3.0 are decreases of 0.09 percent and 0.54 percent for the tractor and vocational vehicle standards, respectively. The tractor standards resulting from GEM 3.5.1 ranged from 0.29 percent below to 0.15 percent above the GEM 3.0 standards. The vocational vehicle standards resulting from GEM 3.5.1 ranged from 0.32 percent above to 1.45 percent below the GEM 3.0 standards. A summary of the process taken to calculate the vehicle standards using GEM and a comparison of the results generated by GEM 3.0 and GEM 3.5.1 are provided in a docket memo.

We are finalizing GEM 3.5.1 without adopting adjustment factors in the related test procedures. In the same memo noted previously, we compare the GEM 3.8 results to those from GEM 3.0. In the supplemental proposal, EPA proposes GEM 3.8 and corresponding adjustment factors to adjust the results to more closely match the results produced by the original GEM 3.0 version and we intend to issue a final rule before the start of model year 2022. If finalized as proposed, we would limit the potential impact on effective stringency due to a change in GEM versions to model year 2021 only, which should have a minimal impact on the effective stringency and environmental benefits of the overall Phase 2 program.

6. Aerodynamic Test Procedures

EPA proposed several updates to the testing and modeling provisions of 1037 subpart F related to aerodynamic testing and requested comment on general improvements to the aerodynamic test procedures and compliance provisions (see 85 FR 28147). This section presents the changes we are adopting to aerodynamic test procedures after consideration of comments received. Additional details on these and other aerodynamic amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments.

a. Aerodynamic Measurements for Tractors

The aerodynamic drag of a vehicle is determined by the vehicle's coefficient of drag (C_d), frontal area, air density and speed. The regulations in § 1037.525 allow manufacturers to use a range of techniques, including wind tunnel testing, computational fluid dynamics, and constant speed tests. This broad approach is appropriate given that no single test procedure is superior in all aspects to other approaches. However, we also recognized the need for consistency and a level playing field in evaluating aerodynamic performance. To address the consistency and level playing field concerns, EPA adopted an approach that identified coastdown testing as the reference aerodynamic test method, and specified a procedure to align results from other aerodynamic test procedures with the reference method by applying a correction factor (F_alt-aero) to results from alternative methods (§ 1037.525(b)). We are adding a sentence to the introductory text of § 1037.525 to clarify that coastdown testing is the “reference method for aerodynamic measurements”.

In the proposed rule, we proposed to separate § 1037.525(b)(1) into a paragraph (b)(1) defining F_alt-aero and a new paragraph (b)(2) allowing manufacturers to assume F_alt-aero is constant for a given alternate method. We are finalizing two separate paragraphs and the subsequent renumbering of the remaining paragraphs as proposed except as explained here. Our proposed update to the definition of F_alt-aero in Equation 1037.525-1 and the related text in § 1037.525(b)(1) inadvertently removed the definition of effective yaw, c_eff, which is used throughout § 1037.525 and incorrectly replaced the C_dA variables measured at ψ_eff with wind-averaged C_dA values, as noted in comment by EMA. We agree that Equation 1037.525-1 should continue to be based on the definition from HD GHG Phase 2 final rule such that F_alt-aero is a function of the coefficient of drag areas at the effective yaw angle. We are finalizing paragraph (b)(1) with the same Equation 1037.525-1 as the current requirement but with the updated variable names throughout § 1037.525 (and where referenced in § 1037.525(h)(12)(v)) to more clearly relate the drag areas to the defined effective yaw variable, as recommended by EMA. We are also adding a “Where:” statement to Equation 1037.525-1 to define the variables in that equation and are restoring the existing language we proposed to remove that defines the effective yaw angle to apply for Phase 1 and Phase 2 compliance.

We proposed and received no adverse comments on two additional changes in § 1037.525(b). In paragraph (b)(3), we proposed and are finalizing removal of the sentence “Where you have test results from multiple vehicles expected to have the same F_alt-aero, you may either average the F_alt-aero values or select any greater value.” By removing this statement, we are allowing manufacturers the flexibility to propose a method for calculating their F_alt-aero from multiple test vehicles that suits their unique compliance margin targets. In paragraph (b)(5), we proposed to add a statement that manufacturers may test earlier model years than the 2021, 2024, and 2027 model years specified and are finalizing additional clarifying text and a new example. We are finalizing two additional typographical edits correcting references to our renumbered paragraphs in the paragraph (b)(5). The reference to “paragraph (b)(2)” was corrected to paragraph (b)(3) and the reference to “this paragraph (b)(4)” was corrected to paragraph (b)(5). Finally, we are adding the phrase “drag area from your alternate method” to describe the previously undefined term, C_dA_alt.

EPA proposed a change to § 1037.525(b)(7), to clarify that the use of good engineering judgment with respect to the specified tractor-trailer gap dimension “applies for all testing, including confirmatory and SEA testing”. Both EMA and Volvo requested further clarification through use of an example. We are finalizing three clarifying changes to § 1037.525(b)(7). First, we are adding a reference to the tractor-trailer gap specifications in § 1037.501(g)(1)(ii), as requested. Second, we provide an example of good engineering judgment that could be applied to correct a difference between the specified and tested tractor-trailer gaps. Lastly, we clarify that the allowance applies “for certification, confirmatory testing, SEA, and all other testing to demonstrate compliance with standards.”

We also proposed a provision to our regulations at § 1037.525(b)(8) to encourage manufacturers to proactively coordinate with EPA to have compliance staff present when a manufacturer conducts its coastdown testing to establish F_alt-aero values. Section 208 of the Clean Air Act provides EPA broad oversight authority for manufacturer testing. Being present for the testing would give EPA greater confidence that the test was conducted properly, and thus, would make it less likely that EPA would need to conduct aerodynamic confirmatory testing on the vehicle. Consistent with the intent of the proposed revision and EPA's authority under section 208, we are finalizing in § 1037.525(b)(8) a provision that refers to the existing preliminary approval provisions of § 1037.210 with the note that EPA may witness the testing. Section 1037.210 provides an established protocol for manufacturers to coordinate with EPA for testing.

EMA's comment requested additional modifications to the yaw sweep correction provisions in § 1037.525(c), suggesting that coastdown results do not need to be corrected to wind-averaged and that all of paragraph (c)(2) was “unnecessary” because another regulatory provision “serves that function”. Their request appears to be a misunderstanding of the existing regulations. Wind-averaged drag area (C_dA_wa) is a required input for GEM in Phase 2. Paragraph (c)(1) specifies how to calculate C_dA_wa when using an alternate test method and paragraph (c)(2) specifies how to calculate it for coastdown testing. EPA may use coastdown for confirmatory testing and manufacturers may choose to use coastdown testing for all aerodynamic testing. Consequently, paragraph (c)(2) is needed to properly calculate the wind-averaged input required by GEM in these situations. To address any potential confusion on the necessity of both paragraphs under the current regulatory text, we are finalizing three updates to § 1037.525(c) as follows:

• Clarifying the use of the yaw correction provisions by revising paragraph (c) introductory text to add “as specified in § 1037.520” and to remove the phrase “differences from coastdown testing” that only applies to paragraph (c)(1).
• Updating the text of paragraphs (c)(1) and (2) to more clearly communicate that they are two separate options that apply based on which testing method is chosen.
• Adopting the updated drag area variable names from § 1037.525(b).

b. Aerodynamic Measurements for Vocational Vehicles

We did not specifically propose changes to or request comment on our procedures for measuring aerodynamic performance of vocational vehicles in § 1037.527. EMA commented that the existing provisions of § 1037.527 to determine a D C_dA value for vocational vehicles refer to the trailer provisions in § 1037.526; however, § 1037.526 does not specify how to choose an appropriate baseline for vocational vehicles. EMA requested that manufacturers should be able to “choose an appropriate baseline vehicle for the technology and applications”. We are not taking any final action on this issue at this time. However, we are providing a summary of the current provisions and their original intent in this preamble to assist manufacturers.

The current § 1037.527(a) states that D C_dA is determined for vocational vehicles as follows: “Determine D C_dA values by performing A to B testing as described for trailers in § 1037.526, with any appropriate adjustments, consistent with good engineering judgment.” The A to B testing provisions for trailers are specified in § 1037.526(a), where paragraph (a)(1) describes the baseline trailer, paragraph (a)(2) describes the general intent of the A to B test, and paragraph (a)(3) describes how to calculate the D C_dA from the test results.

We acknowledge that the reference to a “standard trailer” in § 1037.526(a)(1) may cause confusion to vocational vehicle manufacturers, since it would be a challenge to identify a single “standard” vehicle to represent the range of vocational applications. However, the baseline trailer description in that paragraph equates to a trailer without aerodynamic components, which is the key aspect of that baseline description the regulatory cross-reference in § 1037.527(a) applies to vocational vehicles. The trailer provision of § 1037.526(a)(2) states that the general intent of the A to B test is to “demonstrate the reduction in aerodynamic drag associated with the improved design”, which can be directly applied to vocational vehicles. The general process of calculating D C_dA in § 1037.526(a)(3) could be applied to vocational vehicles as well, but its reference to test trailer and baseline trailer may cause confusion for reasons similar to those discussed for § 1037.526(a)(1).

Similar to the trailer provision, a vocational vehicle's aerodynamic performance is based on a D C_dA value relative to a baseline vehicle. Manufacturers wishing to perform aerodynamic testing on their vocational vehicles are encouraged to coordinate with their Designated Compliance Officer and use the existing provision in § 1037.527, including its reference to the description of how to do so for the trailer-specific provision in § 1037.526. As noted in § 1037.527(a), we expect manufacturers to make “appropriate adjustments” when applying the cross-referenced provision to vocational vehicle testing consistent with good engineering judgment. When followed, this should result in a manufacturer choosing an appropriate baseline vehicle, similar to the clarification requested by the commenter. For example, a manufacturer may choose an aerodynamic test method, determine a baseline C_dA value (in m²) using a vehicle that represents a production configuration without the aerodynamic improvement, then repeat the same aerodynamic method for a test vehicle that is a nearly equivalent configuration but includes the aerodynamic improvement of interest. In this case, the manufacturer would calculate D C_dA by subtracting the measured drag area for the test vehicle from the drag area for the baseline vehicle. Calculating D C_dA in this manner would generally be consistent with the intent that the test “accurately demonstrate the reduction in aerodynamic drag associated with the improved design” for the vocational vehicle since any improvement to aerodynamic performance would be attributable to the aerodynamic technology on the test vehicle.

c. Computational Fluid Dynamics Procedures

We proposed one correction to our computational fluid dynamics (CFD) provisions of § 1037.532 that replaced the incorrect “or” in paragraph (a)(1) with “and” to include yaw angles of +4.5° and −4.5°. EMA requested three additional modifications related to our CFD provisions. In § 1037.532(a)(3), they requested that we clarify our specified Reynolds number of 5.1 million is based on the 102-inch trailer width as the characteristic length. We agree with this suggestion and updated the language in § 1037.532(a)(3) for clarity that the Reynolds number is based on a 102-inch trailer width consistent with our specifications for a “standard trailer” in § 1037.501(g)(1)(i). EMA also suggested the phrase “the General On-Road Simulation” in § 1037.532(a)(4) be replaced with “an open-road simulation” to avoid confusion with SAE International's revisions of SAE J2966 to incorporate the impact of traffic. We agree that open-road simulation is representative of our initial intent and are updating the regulatory text of § 1037.532(a)(4). See Chapter 2 of our Response to Comments for additional details.

EMA's third request was that we remove the requirement to set the “free stream turbulence intensity to 0.0 percent” in § 1037.532(a)(5), and instead recommended we replace that requirement with a “uniform inlet velocity profile.” EPA is not taking any final action on revision to that paragraph at this time. Furthermore, EPA disagrees with the requested change to paragraph (a)(5). Turbulence intensity is a common parameter in CFD packages and, as described in Chapter 3.2.2.3 of the Final Regulatory Impact Analysis (Final RIA) for the HD Phase 2 Rule, we evaluated a range of turbulence intensities and intentionally specified a value of zero to ensure consistency, stating that “Turbulence intensity must be 0.0 percent.” Manufacturers who wish to use alternative parameters and criteria related to their CFD models, which includes seeking to substitute the specified turbulence intensity with a uniform inlet velocity profile, continue to have the option to seek to do so through requesting EPA approval under § 1037.532(f).

CARB requested EPA add provisions that set a requirement for a maximum limit of computational elements to perform Computational Fluid Dynamics (CFD) simulation, define a specific transient averaging methodology, quantify the uncertainty in using CFD simulation, and assess CFD simulation credibility. We are not taking any final action on these requests, but may consider the changes suggested by the commenter in an appropriate future rulemaking with notice and comment. See our complete response in Chapter 2 of our Response to Comments.

7. Hybrid Powertrain Test Procedures

As explained above in Sections II.A.1 and II.A.2, EPA proposed several updates to the hybrid powertrain test procedures that apply to engine and vehicle standards provisions in 40 CFR 1036.503, 1036.505, 1036.510, and 1036.527, 40 CFR part 1036, appendix B, and 40 CFR 1037.550 related to how to perform hybrid powertrain testing and requested comment on general improvements to the hybrid powertrain test procedure provisions (see 85 FR 28152). This section further explains, in addition to the specific descriptions in Sections II.A.1. and II.A.2. above, the changes we are adopting to hybrid powertrain test procedures after consideration of comments received. Additional details on these and other hybrid powertrain testing and measurement amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments.

a. Hybrid Test Procedures for Engine Standards

EPA worked with industry prior to proposal and also considered input provided during this rulemaking to develop a powertrain test procedure that includes the addition of a transmission model to GEM and options in GEM to test without the transmission present, using the model in its place to be used to certify a hybrid powertrain to the FTP and SET HD GHG Phase 2 greenhouse gas engine standards. The two primary goals of this development process were to make sure that the powertrain version of each test cycle was equivalent to the respective engine cycle in terms of positive power demand versus time and that the powertrain cycle had appropriate levels of negative power demand.

Our current regulations do not have a certification procedure for powertrain certification of heavy-duty hybrid vehicles to any engine standards. The powertrain certification test for certification to both the FTP and SET is carried out by following 40 CFR 1037.550 as described in 40 CFR 1036.505 and 1036.510 and is applicable for powertrain systems located in the P0, P1, P2, and P3 positions.

For this test procedure, EPA is finalizing addition of a vehicle speed and road grade profile to the existing FTP duty cycles for compression-ignition and spark-ignition engines in 40 CFR part 1036, appendix B, and to the SET duty cycle in 40 CFR 1036.505. EPA also is finalizing vehicle parameters to be used in place of those in 40 CFR 1037.550; namely vehicle test mass, vehicle frontal area, vehicle drag area, coefficient of rolling resistance, drive axle ratio, tire radius, vehicle curb mass, and linear equivalent mass of rotational moment of inertias. Under the final test procedure, determination of system and continuous rated power along with the maximum vehicle speed (C speed) is also required using 40 CFR 1036.527. Under the final test procedure, the combination of the generic vehicle parameters, the engine duty-cycle vehicle speed profile, and road grade profile fully defines the system load and this is designed to match up the powertrain load with the compression-ignition engine vFTP, spark ignition engine vFTP, and vSET load for an equally powered engine.

The development of this test procedure was based on the process contained in Global Technical Regulation No. 4. Generally speaking, the final test procedure is powertrain in the loop using a vehicle-based cycle (vehicle speed vs. time and grade vs. time). The final vehicle speed profiles were developed by following SAE 2012-01-0878.

The engine operational profile for engines installed in vehicles depends on the entire vehicle setup, including the use of hybrid systems if applicable, thus the entire vehicle must be considered when certifying a powertrain. Given that heavy duty vehicles can vary quite a bit even though the powertrain configuration remains unchanged, testing of every conceivable configuration is not possible; therefore, a representative average vehicle, consisting of generic vehicle parameters, is used to provide a representative configuration for certification testing. Generic vehicle parameters were developed with the intent of maintaining the same system load for engines installed in conventional vehicles and hybrid systems with the same power rating to maintain comparability in terms of emissions.

EPA is finalizing vehicle parameters for hybrid powertrain testing in place of those in 40 CFR 1037.550 to be used in the vehicle model in 40 CFR 1037.550(f). These final parameters can be found in 40 CFR 1036.505 (via reference from 40 CFR 1036.510 for FTP testing) and included vehicle test mass, M, vehicle frontal area, A_front, vehicle drag area, C_dA, coefficient of rolling resistance, C_rr, drive axle ratio, k_a, tire radius, r, transmission efficiency if the hybrid powertrain is being tested without the transmission, axle efficiency, Eff_axle, vehicle curb mass, M_curb, and linear equivalent mass of rotational moment of inertias, M_rotating. The requirements for the determination of these parameters were taken from the Global Technical Regulation (GTR) No. 4 referenced above.

Under the final test procedure, to align the system demands for conventional and hybrid engines, the generic vehicle parameters are defined as a function of the system's power rating. 40 CFR 1036.527 provides the procedure for determining the peak rated power, P_rated, and continuous rated power of the hybrid system, P_contrated, that goes into the vehicle test mass determination. These revisions also provide a procedure for the determination of the maximum vehicle speed (C speed), vrefC. In general, the process for determining both P_rated and P_contrated is very similar to the GTR No. 4 hybrid system rated power determination procedure with a few exceptions. In the final 40 CFR 1036.527 procedure, the default axle efficiency is 0.955 because that is the default value in GEM. The determination of continuous rated power in the final EPA process versus the system rated power in the GTR No. 4 process is to address the lack of a steady state vehicle test cycle in GTR No. 4. The full throttle test to determine system rated power in GTR No. 4 lasts 50 to 150 seconds and GTR No. 4 determines rated power as peak power during these tests. While this process is appropriate for the FTP, the SET is 2400 seconds long and the extended operation at some high speed and load points can lead to some hybrid systems not being able to sustain peak power over the course of the test due to thermal limitations on the motor generator (generally due to material limitations) and limitations on the battery storage capacity and available usable energy. Under these scenarios, the hybrid system will typically derate the motor generator to thermally protect it, resulting in a sustained peak power that is lower than that determined using the GTR No. 4 process.

Under the final test procedure, the powertrain system rated power determination in 40 CFR 1036.527 includes the determination of both peak and continuous rated power. The peak rated power (P_rated) is used in the transient FTP test procedure, while the continuous rated power (P_contrated) is used in the steady-state SET test procedure. The vehicle C speed, v_refC, is also determined as a result of this process. This is the maximum vehicle speed at which Psys equals Pcontrated.

The final compression-ignition vFTP duty cycle vehicle speed profile was derived from the compression-ignition FTP vehicle duty-cycle developed in SAE 2012-01-0878. In this work, a vehicle FTP cycle and a vehicle SET cycle were created based on the transient diesel engine FTP and engine SET duty cycles. The vehicle cycles are the same duration and have similar power requirements and performance when compared to the engine cycles. The alignment of the engine and vehicle cycles maintain a consistency within vehicle and engine emissions evaluations. The compression-ignition FTP vehicle speed profile is not applicable to the spark-ignition FTP vehicle speed profile due to differences in the engine duty-cycle lengths, speed profiles, and torque profiles. Thus, a separate vehicle speed profile had to be developed for the spark-ignition FTP duty cycle. Using the methodology in SAE 2012-01-0878, a vehicle speed profile was developed for the spark-ignition FTP duty cycle and a comparison between the two cycles can be found in Table II-2. The vehicle speed profiles can be found in Figure II-1 and Figure II-2.

The road gradient profile is designed to further align the powertrain system load for engines installed in conventional vehicles and hybrid systems to eliminate the deviations in cumulative work done between the engine and powertrain test. The grade profiles were developed to align the power versus time and cycle work of the vehicle profiles (compression-ignition vFTP, spark-ignition vFTP, and vSET) to the compression-ignition and spark-ignition FTPs, and SET. The general process was based on the development of the grade profile for the World Harmonized Vehicle Cycle (WHVC). A reference normalized power curve was generated using denormalized torque and speed curves from 50 different compression-ignition engines with multiple engine ratings for the compression-ignition FTP, and SET. The denormalized curves were normalized individually for each engine based on the engine's rated power. The normalized power curves were then averaged to define the final reference normalized power curve. Ten different spark-ignition engine torque curves were used for the spark-ignition FTP. The duty-cycle velocity profile over time was then divided into multiple mini-cycles. Within each mini-cycle, a constant grade was defined in such a way that the energy calculated from the normalized power curve was matched for a given engine power rating. Power ratings between 100 and 500 kW were used to develop the compression-ignition vFTP, spark-ignition vFTP, and vSET duty-cycles. The average slope was calculated from the road grade profiles generated for the power ratings between 100 and 500 kW. The average fixed slope was calculated for every time step along the drive cycle, and a second order polynomial was chosen for the FTP duty-cycles to describe correlation between, and account for the differences in, the average fixed and individual slopes based on the rated power (Prated) of the powertrain. The equation and coefficient descriptions follow:

Where a is error compensation in %/kW², b is error compensation in %/kW, and c is the average fixed slope pattern. Negative road grade is included in the profile to ensured that a representative amount of recuperation energy is provided by the test cycle for hybrid applications. This enables accurate cycle power/work alignment for all vehicles with the FTP duty cycles for both compression-ignition and spark-ignition engines. Example vehicle road grade profiles for a 350 kW compression-ignition and 400 kW spark-ignition engine can be found in Figure II-3 and Figure II-4.

During additional review of the development of the road grade profile for vSET included in the proposal, it became apparent that the powertrain might not be able to achieve the default vehicle C speed of 75.0 mph. To provide a representative maximum vehicle speed and vehicle A and B speeds that are scaled to the C speed in the final test procedure, the determination of vehicle C speed was added as an additional revision to 40 CFR 1036.527. This maximum achievable vehicle speed is used as the vehicle C speed in Table 1 of § 1036.505 and A and B speed are calculated as described in 40 CFR 1036.505. The final test procedure replaces the proposed maximum vehicle C speed and the default vehicle A and B speeds in the proposed additions to Table 1 of § 1036.505 with these calculated speeds. Adding the allowance to scale the vSET test speeds based on the vehicle maximum achievable speed required an accounting of the effect of these lower speeds on the road grade determination. This resulted in an expansion of the proposed second order polynomial equation for the vFTP to include vehicle speed in the final test procedure. The expanded equation and coefficient descriptions follow:

Where a is error compensation in %/kW3, b is error compensation in %/kW2·mi/hr, c is error compensation in %/kW2, d is error compensation in %/(mi/hr)2, e is error compensation in %/kW·mi/hr, f is error compensation in %/kW, g is error compensation in %/mi/hr, and h is the average fixed slope pattern. Negative road grade is included in the profile to ensure that a representative amount of recuperation energy is provided by the test cycle for hybrid applications. This enables accurate cycle power/work alignment for all vehicles with the engine SET duty-cycle.

The final test procedure also includes updates to the road grade coefficients for the compression-ignition and spark-ignition vFTP duty cycles from those proposed. EPA further reviewed the GTR No. 4 process and noted that the work in mini cycles number 4 and 6 was set to zero. This was a policy decision made during the GTR No. 4 process but is not appropriate for the generation of EPA's duty-cycles, which should include the actual work for these two mini cycles. While this improvement results in only a marginal difference from that proposed, it provides a more aligned comparison of work between the engine and vehicle duty-cycles. The result of this was included in the final test procedure in updated coefficients for the compression-ignition vFTP, spark-ignition vFTP, and vSET duty cycles (vSET improvements are in addition to the road grade coefficient updates already discussed). Figure II-5 and Figure II-6 show a comparison of the effect on work matching from changing the mini cycle work in mini cycles number 4 and 6 from zero to the actual work for a 300 kW engine. Note, this final test procedure is limited to hybrid powertrains to avoid having two different testing pathways for non-hybrid engines for the same standards.

b. Hybrid Test Procedures for Vehicle Standards

i. Hybrid Fuel Maps

We are finalizing an option, after consideration of comments received, to generate fuel maps for engine hybrids using the powertrain test procedure in 40 CFR 1037.550. This was done by updating the hybrid engine test procedures finalized in 40 CFR 1036.503, 1036.505, 1036.527, and 1037.550 and include the addition of a transmission model to GEM and options in GEM to test without the transmission present, using the model in its place.

ii. Mild Hybrid Certification

Under the Phase 2 regulations, manufacturers must conduct powertrain testing if they wish to take credit for hybrid systems, including mild hybrid systems. However, manufacturers have expressed concerns about the cost of powertrain testing and that the existing procedure may not measure improvements from certain mild hybrid systems. EPA requested comment on alternative means of evaluating mild hybrids noting that manufacturers have asked EPA to consider the following options:

• Allow manufacturers to test a powertrain and apply analytically derived scaling factors to others (e.g., scale by fraction of battery capacity or motor capacity) under 40 CFR 1037.235(h).
• Allow manufacturers to use international test procedures for battery capacity, motor power, and motor efficiency.
• Provide smaller credit (potentially with a volume limit and/or only for limited time) in exchange for less testing (e.g., reduced benefit when using the simplified model spreadsheet that is available under docket no. EPA-HQ-OAR-2014-0827-2109).

Commenters generally responded with support for EPA addressing mild hybrid certification but did not provide any concrete means to address concerns surrounding the cost of powertrain testing. In addition, commenters stated that the existing procedures in the proposal may not measure improvements from certain mild hybrid systems. This section presents the changes we are adopting to hybrid test procedures after consideration of comments received. Additional details on these and other hybrid test procedure amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments.

After further consideration, including the lack of additional input on these mild-hybrid certification options, we have concluded that the engine hybrid test procedure proposed in this rule, is the best pathway for these hybrids. This will allow a manufacturer to test a mild hybrid engine without having to certify the hybrid with a transmission under the powertrain testing option. Finalizing these changes allows the test results to better reflect the performance of mild hybrid's that are not integrated into the transmission, without requiring that the transmission be part of the certified configuration. Finalizing this procedure also allows the test results to be used for additional appropriate vehicles, since the test results will not be limited to the transmission that was included during the test, as is required for non-hybrid powertrains utilizing 40 CFR 1037.550. This mild hybrid engine test procedure was finalize via additions to the hybrid powertrain test procedure revisions in 40 CFR 1036.503, 1036.505, 1036.510, 1036.527, and 1037.550 and includes the addition of a transmission model to GEM and options in GEM to test without the transmission present, using the model in its place.

B. Heavy-Duty Engine GHG Emission Standards and Flexibility

1. Revisions to Credit Provisions for Vocational Engine Emissions Standards

EPA proposed several updates to the credit provisions related to credit provisions for vocational engines and requested comment on these credit provisions (see 85 FR 28145). This section presents the changes we are adopting to vocational engine credit provisions after consideration of comment received. Additional details on comment on these credit provisions and our response are available in Chapter 2.4 of our Response to Comments.

In developing the baseline emission rates for vocational engines in the final Phase 2 rulemaking, we considered MY 2016 FTP certification data for diesel engines, which showed an unexpected step-change improvement in engine fuel consumption and CO₂ emissions compared to data considered in the proposed rule. The proposed baseline emission rates came from the Phase 1 standards, which in turn were derived from our estimates of emission rates for 2010 engines. The underlying reasons for this shift in the 2016 Phase 2 final rule were mostly related to manufacturers optimizing their selective catalytic reduction (SCR) thermal management strategy over the FTP in ways that we (mistakenly) thought they already had in MY 2010 (i.e., the Phase 1 baseline).

As background, the FTP includes a cold-start, a hot-start and significant time spent at engine idle. During these portions of the FTP, the NO_X SCR system can cool down and lose NO_X reducing efficiency. To maintain SCR temperature, manufacturers initially used a simplistic strategy of burning extra fuel to heat the exhaust system. However, during the development of Phase 1, EPA believed manufacturers were using more sophisticated and efficient strategies to maintain SCR temperature. EPA's misunderstanding of the baseline technology for Phase 1 provided engine manufacturers the opportunity to generate windfall credits against the FTP standards.

For the Phase 2 final rule, EPA revised the baseline emission rate for vocational engines to reflect the actual certified emission levels. The Phase 2 vocational engine final CO₂ baseline emissions are shown in the table below. More detailed analyses on these Phase 2 baseline values of tractor and vocational vehicles can be found in Chapter 2.7.4 of the Phase 2 Final RIA.

EPA did not allow the carryover of Phase 1 vocational engine credits into the Phase 2 program, consistent with these adjustments to the baselines. Since this issue does not apply for RMC emissions, the restriction was applied only for engines certified exclusively to the FTP standards (rather than both FTP and RMC standards). We believed that allowing engine credits generated against the Phase 1 diesel FTP standards to be carried over into the Phase 2 program would have inappropriately diluted the Phase 2 engine program. However, this was in the context of unadjusted credits.

After further consideration, we now believe that it would not dilute the program if the credits were appropriately adjusted to more accurately reflect improvement over the true baseline levels.

Allowing the portion of the credits that represent actual emission improvements to be carried forward is consistent with our rationale from Phase 2. Thus, we are allowing in § 1036.701(j), for the purpose of carrying Phase 1 credits into the Phase 2 program, and not compliance with Phase 1 standards, that manufacturers may recalculate the credits in their initial Phase 1 averaging, banking, and trading (ABT) vocational engine averaging set relative to the Phase 2 baseline engine values. The recalculated vocational engine credits for an ABT averaging set will be allowed into the Phase 2 engine program to the same extent as tractor engine credits. Cummins submitted a late comment (see Docket ID EPA-HQ-OAR-2019-0307-0066) requesting clarification of whether manufacturers would have the option of applying these vocational carryover provisions to one ABT averaging set but not another (i.e., that EPA would not require the recalculation of all averaging sets.) This final rule affirms that recalculation of vocational credits is to be applied to all engines within an individual ABT averaging set and that other averaging sets, such as tractors, are not affected by these vocational carryover provisions. EMA commented that manufacturers should be able to opt in to recalculating credits on an engine family by engine family basis, as applying this adjustment to all engine families could affect existing Phase 1 compliance for engines above the Phase 2 baseline value. However, EPA is only allowing this recalculation for the purpose of determining the amount of credit that can be carried into the Phase 2 program, and adjusting the credits for all the engine families a manufacturer chose to include in their initial ABT averaging set for Phase 1 program properly accounts for the net credits that can be carried forward. In the ABT program, all engine families within an averaging set are used in the calculation of credits, and manufacturers cannot pick and choose which engine families are used in that calculation.

As noted in the Phase 2 final rule, allowing additional flexibility for compliance with engine standards does not cause any increase in emissions because the manufacturers must still comply with the vehicle standards (See 81 FR 73499, October 25, 2016). However, this flexibility could allow some manufacturers to find a less expensive compliance path.

2. Special Flexibility for Vocational Engines and Credits

EPA requested comment on several updates to the special flexibility provisions for vocational engines (see 85 FR 28145). This section presents the regulatory changes we are adopting after consideration of comments received. Additional details on comments received on these provisions and our responses are available in Chapter 2.4 of our Response to Comments.

In the existing regulations at 40 CFR 1036.150(p), EPA provided special flexibility for engine manufacturers that certify all their model year 2020 engines within an averaging set to the model year 2021 FTP and SET standards and requirements. Where 40 CFR 1036.150(p) applies, paragraph (p)(1) specifies that GHG emission credits that manufacturers generate with model year 2018 through 2024 engines may be used through model year 2030, instead of being limited to a five-year credit life as specified in 40 CFR 1036.740(d). Note that under the Phase 2 final rule this provision in effect only applies to manufacturers of tractor engines, as under 40 CFR 1036.701(j) EPA did not allow the carryover of Phase 1 vocational engine credits into the Phase 2 program (81 FR 73499, October 25, 2016). Where 40 CFR 1036.150(p) applies, paragraph (p)(2) specifies that manufacturers are also allowed to certify model year 2024 through 2026 tractor engines to alternative standards that are slightly higher than the otherwise applicable standards. Note that in the table of alternative standards in the Phase 2 final rule EPA included values for medium and heavy heavy-duty vocational engines, but these values are identical to the Phase 2 standards and not slightly higher due to our concerns about windfall credits if carryover of Phase 1 credits were allowed.

The applicability of 40 CFR 1036.150(p) is based on the choices manufacturers made when certifying their MY 2020 engines. Instead of certifying engines to the final year of the Phase 1 engine standards, manufacturers electing the alternative instead certified to the MY 2021 Phase 2 engine standards. Because these engine manufacturers reduced emissions of engines that would otherwise have been subject to the more lenient MY 2020 Phase 1 engine standards, there can be a net benefit to the environment. These engines do not generate credits relative to the Phase 1 standards but instead generate credits relative to the pulled ahead MY 2021 Phase 2 engine standards. Because the vehicle standards themselves are unaffected, the alternative MY 2024-2026 engine standards will not dilute or diminish the overall GHG reductions or fuel savings of the program. Vehicle manufacturers using engines subject to the alternative MY 2024-2026 standards would need to adopt additional vehicle technology (i.e., technology beyond that projected to be needed to meet the engine standards) to meet the applicable vehicle GHG standards. The result is that the vehicles would still achieve the same GHG emissions in use.

The proposed rule included an amendment to address the concern regarding Phase 1 windfall credits and requested comment on the possibility of a similar set of alternative standards for vocational engines. CARB and Volvo commented that they support these changes and flexibilities. Cummins commented opposing both the alternative MY 2024 through 2026 vocational engine standards and extending the life of credits generated from early compliance with Phase 2 vocational standards. The American Council for an Energy-Efficient Economy commented opposing extending the life of vocational engine credits generated in Phase 1, stating that doing so does not result in emission reductions but would increase emissions and reduce the rule's overall stringency. Cummins also commented that manufacturers had already developed and certified MY 2020 products without consideration of these changes, and even if post hoc recertification was possible, allowing them now would potentially be an advantage or disadvantage to individual manufacturers.

As discussed in section II.B.1, we are finalizing provisions on calculating credits relative to a baseline that addresses these windfall credit concerns, which also results in the extended credit life flexibility under 40 CFR 1036.150(p)(1) now being available to vocational vehicles that qualify under 40 CFR 1036.150(p). We are also finalizing a set of alternative standards for vocational engines, as shown in Table II-4.

The Phase 2 standards are implemented in three MY steps: 2021, 2024, and 2027. The largest step change in stringency occurs in MY 2024, where approximately two-thirds of the total numeric reduction in the MY 2021 through MY 2027 standards is achieved, with the remaining one-third occurring in MY 2027. For the alternative tractor engine standards, EPA reversed the magnitude of the MY 2024 and MY 2027 step changes, where the MY 2024 alternative standard represents one-third of the total numeric reduction and is slightly higher than the Phase 2 standard. The standards at the beginning (MY 2021) and ending (MY 2027) steps of the Phase 2 program remain the same in either case, and only the level of decrease in standard for MY 2024 changes with the alternative standards. EPA determined the alternative standards for vocational engines by adjusting the magnitude of the MY 2024 standard in the same manner as used to determine the alternative tractor engine standards in the Phase 2. The Phase 2 vocational engine standards decrease by 10 g/hp-hr between MY 2021 and MY 2027, with a 7 g/hp-hr step change in the MY 2024 standard (approximately two-thirds of the total numeric reduction) and a 3 g/hp-hr step change in MY 2027. For the alternative vocational engine standards in MY 2024-2026, we are adopting a 3 g/hp-hr reduction from the MY 2021 standard (from 545 to 542 g/hp-hr for medium heavy-duty (MHD) and 513 to 510 g/hp-hr for heavy heavy-duty) instead of 7 g/hp-hr. EPA believes that allowing these slightly higher (approximately 0.7 to 0.8% compared to the Phase 2 final rule) engine standards for vocational vehicles is justified, as the overall vehicle standards will still be met. Engine development and vehicle technology choices are pathways to meeting overall vehicle standards, as is the use of credits generated by early compliance. EPA's alternative engine standards provisions for vocational vehicles for MYs 2024-2026 allows manufacturers flexibility to choose the mix of engine and vehicle technologies that will comply with the standards. As noted in the Phase 2 final rule and this rule's proposal, EPA views this type of alternative as being positive from the environmental and energy conservation perspectives, as vehicle-level emission standards remain the same, but manufacturers are provided with significant flexibility on engine emission standards and credit life provisions that may reduce their compliance costs.

Regarding the adverse comments received, including whether or not manufacturers had the opportunity to consider these changes prior to MY 2020, these changes correspond to the corrected approach to Phase 1 credit calculations explained in Section II.B.1 above. At the time of the Phase 2 final rule, we believed that allowing Phase 1 vocational engine credits, without adjustment, to be carried over to the Phase 2 program would result in “windfall” credits, or dilution of the benefits of the Phase 2 program, and we adopted restrictions to limit their use. However, after the Phase 2 final rule we recognized that an alternative to restricting Phase 1 vocational engine credits because of windfall concerns would be to adjust credits earned in Phase 1 downward, relative to a baseline of the lower Phase 2 emissions standards, and in doing so, we would be extending to vocational engine manufactures the same flexibilities that were provided to tractor engine manufacturers. In this final rule we are allowing the vocational engine credits generated in Phase 1 to be adjusted downward and used in Phase 2 program through MY 2030, just as they were for tractors. In setting lower baseline emission values for Phase 1 vocational engine credits and providing the corresponding program flexibilities, EPA does not intend to advantage or disadvantage any manufacturer. Rather, we are removing restrictions that were applied only to vocational engines but no longer should be applied now that we are finalizing provisions that provide a proper accounting of the emission improvements realized by manufacturers who chose to certify their MY 2020 engines to the MY 2021 Phase 2 standards, so vocational and tractor engines are treated the same. In addition, the revised MY 2024-2026 alternative standards for vocational engines, while slightly higher than those in the Phase 2 final rule by 0.7 to 0.8%, do not reduce the overall stringency of the Phase 2 program, but instead reflect the alternative standards we would have adopted in the Phase 2 final rule alongside the similar tractor provisions, and for the same reasons we finalized those tractor provisions, had we considered adjusting baseline emission rates used for calculating Phase 1 credits. Manufacturers that qualify to use the alternative MYs 2024-2026 engine standards accelerated their compliance with the more stringent MY 2021 Phase 2 standards by one model year. As we explained in the Phase 2 final rule, because the vehicle standards themselves are unaffected, these alternative engine standards will not dilute or diminish the overall GHG reductions or fuel savings of the program. Vehicle manufacturers using engines subject to the alternative MYs 2024-2026 standards will need to adopt additional vehicle technology (i.e., technology beyond that projected to be needed to meet the engine standard) to meet the applicable vehicle GHG standards. The result is that the vehicles using engines that comply with the alternative standards will still achieve the same overall GHG emissions in use. EPA believes that these alternative standards are appropriate, and allowing alternative engine standards for vocational vehicles that qualify is justified, for these reasons, and that vocational engine manufacturers who met the Phase 2 engine standards one year in advance of the MY 2021 implementation date should have the same flexibility as tractors to earn and use those credits through MY 2030.

3. Confirmatory Testing of Engines and Measurement Variability

EPA proposed updates to the procedure for confirmatory testing of the fuel mapping test procedure related to providing an interim 2% allowance during confirmatory testing of the fuel mapping test procedure finalized in the Phase 2 final rule and requested comment on “. . . whether it appropriately balances the impacts of testing variability for fuel maps” (see 85 FR 28146, May 12, 2020). This section presents the changes we are adopting to the confirmatory testing portion of the fuel mapping test procedure after consideration of comments received. Additional details on these comments and our responses are available in Chapter 2 of our Response to Comments.

During the Phase 2 rulemaking, manufacturers raised concern about measurement variability impacting the stringency of the engine GHG standards and fuel map requirements. As noted in the Phase 2 final rule, the final standards were developed to account for this. (81 FR 73571, October 25, 2016). Manufacturers raised particular concern about variability of fuel map measurements because neither they nor EPA had sufficient experience measuring fuel maps (in a regulatory context) to fully understand the potential impacts of measurement variability. We estimated the fuel map uncertainty to be equivalent to the uncertainty associated with measuring CO₂ emissions and fuel consumption over the FTP and SET cycles, which we estimated to be about one percent. However, the Phase 2 final rule noted that we were incorporating test procedure improvements that would further reduce test result uncertainty. We also noted that “[i]f we determine in the future . . . that the +1.0 percent we factored into our stringency analysis was inappropriately low or high, we will promulgate technical amendments to the regulations to address any inappropriate impact this +1.0 percent had on the stringency of the engine and vehicle standards.” (81 FR 73571, October 25, 2016)

In conjunction with this intention, EPA has worked with engine manufacturers to better understand the variability of measuring fuel maps using the test procedures and cycles specified by EPA in the Phase 2 final rule. Through that work, we identified several sources of variability that can be reduced by making small changes to the test procedures. EPA is adopting these changes, as explained in Sections II.A.1 through II.A.3 of this final rule.

SwRI performed emission measurements in multiple test cells and identified distributions of error for other test inputs such as measured fuel properties and calibration gas concentrations. SwRI then used a Monte Carlo simulation to estimate a distribution of errors in measured fuel maps. After reviewing the results, EPA had several significant observations which we discussed in the proposal for this final rule and which EPA confirms in this final action:

1. The variability of measuring CO₂ and fuel consumption during fuel mapping is greater than the one percent assumed in the Phase 2 final rule. Variability from vehicles without idle test cycles is <1.8% (1.68 to 1.8%), while variability from vehicles with idle test cycles is <2.8% (2.0 to 2.79%).

2. The variability of measuring CO₂ and fuel consumption during the fuel mapping procedure is roughly the same as that of the FTP and SET cycles, 3.34% for the FTP and 1.99% for the SET.

3. Measuring CO₂ and fuel consumption at idle is particularly challenging.

4. The data obtained during the test program at SwRI did not include all the test procedure changes being adopted in 40 CFR parts 1036 and 1037 that will further reduce fuel mapping test variability and therefore the variability is likely to be lower than reported by the SwRI.

Manufacturers have indicated they are concerned about the possibility of EPA changing an official fuel map result as a consequence of EPA confirmatory testing where the measured maps were within an expected range of variability. In the context of the SwRI test program, EPA observed similarity between the range of variability of measuring fuel maps and the range of variability of measuring CO₂ and fuel consumption over the FTP and SET cycles (measurements for which EPA has already determined in both Phase 1 and Phase 2 that no such allowances are needed). These results indicate that there is no additional source of increased variability associated with the fuel mapping test procedure and suggest that manufacturers should be able to comply without any special provisions. Additionally, the data we have available indicates that the manufacturers may potentially over time be able to take advantage of the 2% allowance, resulting in a reduction in stringency of the standards. We anticipate that this would not happen over the next few model years, as manufacturers will need time to implement the revised test procedures adopted in this rule that will reduce the variability of the fuel map test procedure to levels at or below the variability of the FTP and SET test procedures.

After considering the comments received, we are adopting the limited transitional approach aimed at addressing the manufacturers' variability concerns. As manufacturers implement this rule's revised test procedures to reduce variability, we will analyze and compare a manufacturer's declared and measured fuel maps to those that result from our confirmatory testing, with the goal of ensuring the long-term integrity of the Phase 2 program. We are codifying the interim provision for model years 2021 and later in 40 CFR 1036.150, under which EPA will not replace a manufacturer's fuel maps during confirmatory testing if the difference between the EPA-measured fuel maps and the manufacturer's declared maps is less than or equal to 2.0 percent. We may revisit the interim 2% allowance in a future rulemaking.

EPA also intends to further review data and developments in this area. We intend to review this provision as we learn more about the impact of measurement variability on measured and declared fuel maps submitted during the certification process for future model years (including the full impact of the test procedure improvements that are intended to reduce measurement variability), which may inform whether we determine additional action is warranted in the future with respect to fuel mapping variability. We also intend to enter into a round robin study of criteria and GHG pollutant engine testing variability with interested engine manufacturers, with the involvement of the Truck and Engine Manufacturer's Emission Measurement and Testing Committee. This data will add to the existing knowledge regarding the variability of the FTP, SET and fuel mapping test procedures and may help inform if future action is needed to further improve the test procedures.

We are also finalizing an algorithm for comparing fuel maps. Because fuel maps are multi-point surfaces instead of single values, it would be a common occurrence that some of EPA's points would be higher than the manufacturer's while others would be lower. This algorithm was inadvertently proposed as an interim provision in 40 CFR 1036.150(q) along with the 2.0 percent variability allowance. The algorithm and fuel map comparison process during a confirmatory test is needed for confirmatory testing regardless of an allowance. Therefore, in this final rule the algorithm and all supporting text are located at 40 CFR 1036.235(c)(5). The limited interim 2.0 percent variability allowance is located at 40 CFR 1036.150(q).

EPA's measured fuel maps will be used with GEM according to 40 CFR 1036.540 to generate emission duty cycles which simulate several different vehicle configurations, generating emission results for each of the vehicles for each of the duty cycles. Each individual duty cycle result will be weighted using the appropriate vehicle category weighting factors in Table 1 of 40 CFR 1037.510 to determine a composite CO₂ emission value for that vehicle configuration. Note that the equation is being finalized to use values before rounding as this is consistent with the provisions in 40 CFR 1065.20 to not round intermediate values. When the process is repeated for the manufacturer's fuel maps, the average percent difference between fuel maps will be calculated as:

Where:

i = an indexing variable that represents one individual weighted duty cycle result for a vehicle configuration.

N = total number of vehicle configurations.

e_CO2compEPAi = unrounded composite mass of CO₂ emissions in g/ton-mile for the EPA confirmatory test.

e_CO2compManu = unrounded composite mass of CO₂ emissions in g/ton-mile for the manufacturer declared map.

4. Other Minor Heavy-Duty Engine Amendments

EPA proposed three additional updates to the testing and measurement provisions of 40 CFR part 1036, related to measuring emissions from heavy-duty engines and requested comment on general improvements to the engine test procedures and compliance provisions (see 85 FR 28147). This section presents these three additional changes we are adopting to engine test procedures. Additional details on these and other engine testing and measurement amendments or clarifications requested by commenters and our responses are available in Chapter 2 of the Response to Comments.

• Correcting the assigned N₂O deterioration factor in § 1036.150(g). In the Phase 2 proposed rule, EPA proposed to lower the N₂ O standard from 0.10 g/hp-hr to 0.05 g/hp-hr for model year 2021 and later diesel engines. In that context, we also proposed to lower the assigned deterioration factor (DF) from 0.020 g/hp-hr to 0.010 g/hp-hr for model year 2021 and later diesel engines. EPA explained in the preamble to the Phase 2 final rule that we were not finalizing the change to the standard (81 FR 73530, October 25, 2016), but inadvertently finalized the proposed DF change in the regulations. We proposed in this rulemaking to correct this error, consistent with EPA's clear statement in the Phase 2 final rule that we were not finalizing the change to the standard. However, given that finalizing the assigned DF of 0.01 g/hp-hr for N₂ O in the regulations was an oversight on EPA's part in the Phase 2 final rule and that the Phase 2 final rule was inadvertently internally inconsistent, and after consideration of EMA's comment that manufacturers will not have time to correct or account for a change in the assigned DF in time for their MY 2021 certifications, we are deferring changing the assigned DF to 0.02 g/hp-hr until MY 2022 within the revisions finalized in this rulemaking.
• Clarifying a reference to non-gasoline engine families in § 1036.705(b)(5). The second sentence of § 1036.705(b)(5) is intended to refer to non-gasoline engine families. However, the existing text is not clear. As written, it can be read to mean that gasoline engine families may not generate emission credits. EPA is adding “non-gasoline” to clarify the intended meaning.
• Engine families. We are revising § 1036.230 to allow engine families to be divided into subfamilies with respect to CO₂. This allowance simplifies the certification process without changing the overall requirements.
• Adding a summary of previously applicable emission standards as appendix A of part 1036. The new appendix is being provided for reference purposes only regarding previously applicable emission standards and will cover regulatory text being deleted from 40 CFR part 86.

Except as noted above, we received no adverse comments on these proposed amendments and are adopting them without modification.

C. Heavy-Duty Vehicle GHG Emission Standards and Flexibility

1. Aerodynamic Compliance Provisions

In addition to the aerodynamic test procedure amendments described in Section II.A.6, we proposed several updates to § 1037.150(s) as it relates to EPA's confirmatory testing of aerodynamic parameters and § 1037.305 as it relates to our selective enforcement audit (SEA) procedures. We also requested comment on general improvements to the aerodynamic compliance provisions (see 85 FR 28147). This section presents the changes we are adopting to our confirmatory testing and SEA procedures after consideration of comments received. Additional details on these and other aerodynamic amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments.

a. Confirmatory Testing for F_alt-aero

As described in 40 CFR 1037.235(c), EPA may perform confirmatory testing on a manufacturer's vehicles, including a vehicle tested to establish the F_alt-aero value. The regulations also include an interim provision in § 1037.150(s) that outlines how EPA may and when EPA will not replace a manufacturer's F_alt-aero value based on confirmatory test results. This interim provision connects EPA's confirmatory testing to the audit procedures of § 1037.305. In keeping with the principle that good engineering judgment would generally call for more data rather than selecting a single value, and after consideration of comment, EPA is finalizing our proposed provision to require EPA to perform a minimum of 100 valid runs before replacing a manufacturer's F_alt-aero value in confirmatory testing with some additional clarifications in § 1037.150(s).

CARB commented in support of increasing the number of runs from SEA to 100 to limit false failures, but requested in comment to know the origin of the proposed minimum 100 valid runs for confirmatory testing. Our intent with the finalized requirement for 100 valid confirmatory runs is to maintain consistency with the existing regulatory language adopted in the Phase 2 final rulemaking for SEA testing. The existing § 1037.305(a)(7)(iii) states: “The vehicle passes if you perform 100 coastdown runs and C_dA_wa-upper is greater than and C_dA_wa-lower is lower than the upper limit of the bin to which you certified the vehicle.” Similarly, as noted below in Section II.C.1.b, we are also finalizing our corresponding proposed language in the audit procedures of § 1037.305(a)(5) clarifying that manufacturers must perform a minimum of 24 runs to pass and a minimum of 100 runs to fail.

EMA requested additional modifications to § 1037.150(s) regarding EPA's approach to calculating a new F_alt-aero value in confirmatory testing. EMA suggested that the regulation more explicitly connect to the SEA procedures for pass/fail criteria and the coastdown procedures for calculating F_alt-aero. They also suggested we directly outline how EPA will replace a manufacturer's F_alt-aero. EMA suggested that EPA calculate two F_alt-aero values and apply the average of those values to replace a manufacturer's value. We agree with EMA's suggestions to clarify the connections to the SEA procedures of § 1037.305 and the coastdown test procedures of § 1037.528 and we updated § 1037.150(s) accordingly. While we generally agree that additional data is preferable, we are not committing to calculating multiple F_alt-aero values, as requested by EMA, due to consideration of potential resource constraints; however, we have revised the regulatory language to allow for it. We also are not finalizing an approach to calculate the final F_alt-aero when there are multiple values. Our revised § 1037.150(s) states that EPA will “will generate a replacement value of F_alt-aero based on at least oneC_dA value and corresponding effective yaw angle”.

Additionally, as noted in the proposal regarding § 1037.150(s), we recognize that test conditions for coastdown testing are an important consideration. For our confirmatory testing, EPA intends to minimize the differences between our test conditions and those of the manufacturer and we proposed a note in § 1037.150(s) stating our intent to test at similar times of the year. EMA requested additional regulatory language regarding our intent to test at the same location as well as time of year. We are expanding our proposed note in § 1037.150(s) to include our intent to test at both the same time of year and the same location, subject to certain considerations. More specifically, we emphasize that the note in § 1037.150(s) is not a commitment by the agency due to the limited number of coastdown test facilities, the challenges of scheduling time for testing, and our prerogative to choose an alternative facility if we have concerns about the original test location. Our revised language in § 1037.150(s) states that we intend to test “at similar times of the year where possible and at the same location where possible and when appropriate.”

b. Selective Enforcement Audits for Tractors

We proposed and received no adverse comments to three typographical edits to our aerodynamic testing audit procedures for tractors in § 1037.305. We are finalizing those three edits as proposed and additional editorial edits as follows:

• Section 1037.305—Replaced reference to 40 CFR 1068.420 with the range “40 CFR 1068.415 through 1068.425” as proposed.
• Section 1037.305(a)—Rephrased “whether or not a tractor fails to meet” to the more concise “whether a tractor meets”.
• Section 1037.305(a)(2)—Corrected “coastdown effective” to “coastdown effective yaw angle” as proposed.
• Section 1037.305(a)(7)—Added a missing “m2” following the bin value of 5.95 in the example as proposed. Editorial revisions to remove passive voice.

In comment, EMA suggested additional revisions to § 1037.305(a) allowing manufacturers to apply good engineering judgment in their selective enforcement audit (SEA) testing if a production vehicle could not be configured to meet the trailer height specified in § 1037.501(g)(1)(i). We accept that a future production vehicle may be designed such that it cannot be configured to match a trailer that meets our current definition of standard trailer. We are finalizing a broader revision to address all such scenarios where a production vehicle cannot be configured to match a trailer that meets our current definition of standard trailer, including but not limited to height, that will address EMA's specific concern with meeting the standard trailer's height requirements. We are adding language to clarify that a manufacturer may seek EPA approval to use an alternate or modified vehicle configuration, consistent with good engineering judgment, if EPA chooses to audit a production vehicle configuration that cannot meet any of the standard trailer requirements specified in § 1037.501(g)(1).

As noted in Section II.C.1.a, we proposed and are finalizing a provision in § 1037.150(s) to require EPA to perform a minimum of 100 valid runs before replacing a manufacturer's F_alt-aero value in confirmatory testing. Similarly, we are finalizing our corresponding proposed language in the audit procedures of § 1037.305(a)(5) clarifying that manufacturers must perform a minimum of 24 runs to pass and a minimum of 100 runs to fail. Finally, we received no adverse comments and are finalizing the proposed regulatory language in § 1037.305(a)(7)(v) allowing manufacturers to continue testing and to generate additional data that EPA may consider in our pass/fail determinations.

2. Idle Reduction Technologies

EPA proposed several provisions related to idle reduction technologies. This section presents the changes we are adopting after consideration of the comments received. See Chapter 2 of our Response to Comments for further details, including additional idle reduction amendments or clarifications requested by commenters and our responses.

a. Extended-Idle Reduction for Tractors

The Phase 1 version of GEM gives credit for extended idle emission reduction technologies that include a tamper-proof automatic engine shutoff system (AESS), with few override provisions. Phase 2 GEM gives credit for a wider variety of idle reduction strategies, recognizing technologies that are available on the market today, such as auxiliary power units (APUs), diesel fired heaters, and battery powered units. For example, a tamper-proof AESS with a diesel APU would be credited with a 4 percent reduction in emissions, while an adjustable AESS with a diesel fired heater would be credited with a 2 percent reduction in emissions (81 FR 73601, October 25, 2016).

Our proposal to revise § 1037.520(j)(4) to include GEM input values for combinations of these technologies received support from CARB, EMA, and Volvo and we are finalizing our proposed combinations of idle reduction technologies as shown in Table II-5. Adding these values to GEM reduces the compliance burden for manufacturers who would otherwise need to apply for off-cycle credits for these technology combinations. The values of these technology benefits were determined using the same methodology used in the Phase 2 final rule.

b. Idle Reduction Overrides

In 40 CFR 1037.660, we identify three idle reduction technologies (i.e., automatic engine shutdown, neutral idle, and stop-start) and specify how these systems must operate to qualify for GEM credit. Included among those provisions are allowances for overriding these systems where it may damage the engine or create a safety issue for the vehicle occupants or service personnel. This section highlights the some of the idle reduction override provisions we are adopting, either as proposed or further revisions after consideration of comments received.

i. Automatic Engine Shutdown (AES) Overrides

While we did not specifically propose or request comment on AES overrides, New Flyer (a bus manufacturer) commented that the override condition for AES systems during servicing in § 1037.660(b)(1)(ii) (cross-referenced under the existing regulations for vocational vehicles in § 1037.660(b)(2)(i)) could pose a safety risk to maintenance personnel. They stated that maintenance personnel may not have a diagnostic scan tool required to deactivate the system and some maintenance may require longer than the current 60-minute limit before reactivation. New Flyer suggested an “open engine compartment” would be a more appropriate override condition.

After consideration of New Flyer's safety concern for vocational vehicles, we are revising § 1037.660(b)(2) to allow a vocational vehicle's AES system to delay shutdown if necessary while servicing the vehicle without the scan tool requirement and time limit. Our final revision removes the cross-reference in § 1037.660(b)(2)(i) to that particular provision in § 1037.660(b)(1) and replaces it with a new provision in § 1037.660(b)(2)(ii). Our new provision allows a delay in shutdown for vocational vehicles if the engine compartment is open and replaces the regulatory text regarding unsafe cab temperatures in the current § 1037.660(b)(2)(ii), which is redundant with the existing cross-reference to paragraph (b)(1) in paragraph (b)(2)(i). For vocational vehicles, we believe an open engine compartment sufficiently indicates that a vocational vehicle is being serviced and automatic engine shutdown would provide limited environmental benefit. We are not taking final action to revise the tractor-specific provision of § 1037.660(b)(1)(ii) to allow an open engine compartment as a condition for AES override, since the environmental benefits of AES on tractors occurs when these vehicles are parked for extended durations where an open engine compartment may not be a sufficient deterrent for the operator to circumvent the AES.

We are finalizing editorial revisions to § 1037.660(b) so the paragraphs consistently begin with “When”. Additionally, we reordered the paragraphs of § 1037.660(b)(1) to move the servicing provision previously located at paragraph (b)(1)(ii) to paragraph (b)(1)(vi) such that the vocational vehicle AES provisions can continue to reference the range of relevant (b)(1) paragraphs in paragraph (b)(2)(i).

ii. Neutral Idle Overrides

EPA proposed and is finalizing a provision in § 1037.660(b)(3)(ii) that would allow the neutral idle system to delay shifting the transmission into neutral if the transmission is in reverse gear (85 FR 28271, May 12, 2020). New Flyer requested an additional override when the vehicles is on a road grade of 6.0 percent or more to prevent the safety concern of vehicle rollback. EPA agrees with this safety concern and is finalizing a provision in § 1037.660(b)(3)(iii) to allow a delay in neutral idle when the vehicle is on a grade greater than or equal to 6.0 percent. EMA requested additional overrides for “safety; thermal protection of the emissions aftertreatment; and maintenance of aftertreatment temperature within a range for adequate emissions control”. EPA is not adopting EMA's suggested override conditions as we do not think that they would likely be appropriate without more specific criteria. Manufacturers continue to have the option to justify the need for additional overrides for their individual systems and seek EPA approval through § 1037.660(b).

iii. Stop-Start Overrides

We requested comment on a specific list of override conditions for stop-start systems (85 FR 28151, May 12, 2020). CARB expressed concern that additional overrides may compromise emissions and requested a requirement that manufacturers bring their proposed overrides to EPA for approval. We are not requiring a “case-by-case” approval process for these overrides, as suggested by CARB, but we note that, in the certification application provisions of § 1037.205(b)(5), manufacturers are required to include a description of their idle reduction technology, including the override conditions of § 1037.660. We believe this continues to be an appropriate level of oversight for these idle technologies and their associated override conditions.

EMA and New Flyer supported the inclusion of all override conditions listed in the proposed rule for comment, but their comments did not expand on the need for any of the individual conditions to be adopted. Each commenter requested additional override conditions and included the rationale for those requests. Our final revisions to § 1037.660(b)(4) cross-reference the provisions for vocational vehicle AES (paragraph (b)(2)) and neutral idle (paragraphs (b)(3)(ii) and (iii)) such that the new open engine compartment, reverse gear, and road grade provisions for those systems also apply for stop-start systems. EPA considered the original list and the commenters' additional suggested override conditions and we are adopting the following additional override criteria specific to stop-start systems to ensure safety and/or effective system operation as noted in § 1037.660(b)(4):

• When the steering angle is at or near the limit of travel to avoid steering wheel kickback during engine start.
• When a wheel speed sensor failure may prevent the anti-lock braking system from detecting vehicle speed.
• When an automatic transmission is in “park” or in “neutral” with the parking brake engaged because the feature is intended to be used during driving operation.
• When a component failure protection mode is active, such as starter motor overheating, which may prevent the engine from restarting.
• When a fault is active on a system component needed to start the engine, which may prevent the engine from restarting.
• When the flow of diesel exhaust fluid is limited due to freezing, because an engine-off condition may further delay thawing and SCR operation.

It was not clear that the remaining override conditions suggested by commenters or presented for comment in the proposed rule pose a widespread concern for safety, vehicle operation, or serviceability, or could not be easily overridden by the driver, and we are not adopting those overrides in our final revisions. However, manufacturers continue to have the option to seek EPA approval for these or additional criteria they believe are needed to protect the engine and vehicle from damage and to ensure safe vehicle operation (see § 1037.660(b)).

3. Weight Reduction

EPA proposed minor revisions to the weight reduction provisions (see 85 FR 28150). This section presents the changes we are adopting after consideration of comments received. See Chapter 2 of our Response to Comments for additional details on some of these amendments, including other amendments or clarifications requested by commenters and our responses.

The regulations in 40 CFR 1037.520 include tables to calculate weight reduction values for using certain lightweight components. The sum of the weight reductions is used as an input to GEM. As noted in Section II.A.2, EPA proposed two changes to Table 8 of that section allowing manufacturers to use the heavy heavy-duty (HHD) values for medium heavy-duty (MHD) vehicles with three axles (i.e., 6x4 and 6x2 configurations) and adding a footnote to the table to clarify that the weight reduction values apply per vehicle (instead of per component) unless otherwise noted. We received no adverse comments to the proposed updates to Table 8 and we are finalizing the two changes.

We received comment from EMA requesting “a process for adding in other weight-savings technologies”. As described in § 1037.520(e)(5), this process is available in the existing off-cycle provisions of § 1037.610 and no further action is needed or being finalized in this rule. EMA also requested clarification on the origin of certain weight reduction values for tires and recommended use of a “base” value for comparison. We note that all the values in Table 6 through Table 8 of § 1037.520 were developed through notice and comment in the HD Greenhouse Gas Emissions Phase 1 and Phase 2 rulemakings based on information as described in the Regulatory Impact Analysis for the rules. We did not propose changes to the weight reduction tables and are not taking any final action at this time to update values to refer to a base weight, but manufacturers continue to have the ability to apply through our off-cycle process.

4. Self-Contained Air Conditioning Units

We proposed a revision to § 1037.115(e) to clarify that it is “intended to address air conditioning systems for which the primary purpose is to cool the driver compartment (85 FR 28151). This would generally include all complete pickups and vans, but not self-contained air conditioning or refrigeration units on vocational vehicles.” CARB and New Flyer requested additional clarification on the phrase “self-contained”. After consideration of submitted comments, we are finalizing a modified version of the proposed changes to § 1037.115(e)(1) that incorporates some of the feedback from commenters. We are maintaining the proposed statement that this provision is intended for A/C systems that cool the driver compartment. We're clarifying that it generally applies to “cab-complete” pickups and vans (see definition at § 86.1803-01) which is more appropriate for heavy-duty than “complete pickups and vans” as proposed. We are expanding the existing statement that the paragraph does not apply for self-contained A/C or refrigeration units by adding the phrases “used to cool passengers” and “used to cool cargo”. Finally, we further clarify that a self-contained system for purposes of this provision is an “enclosed unit with its own evaporator and condenser even if it draws power from the engine.”

5. Manufacturer Testing of Production Vehicles

The regulations require tractor manufacturers to annually chassis test five production vehicles over the GEM cycles to verify that relative reductions simulated in GEM are being achieved in actual production. See 40 CFR 1037.665. We do not expect absolute correlation between GEM results and chassis testing. GEM makes many simplifying assumptions that do not compromise its usefulness for certification but do cause it to produce emission rates different from what would be measured during a chassis dynamometer test. Given the limits of correlation possible between GEM and chassis testing, we would not expect such testing to accurately reflect whether a vehicle was compliant with the GEM standards. Therefore, § 1037.665 does not apply compliance liability to such testing.

The regulation also allows manufacturers to request approval of alternative testing “that will provide equivalent or better information.” Manufacturers have asked us to clarify this allowance and we proposed to revise § 1037.665 to provide an example that the EPA may allow manufacturers to provide CO₂ data from in-use operation, and CO₂ data from manufacturer-run on-road testing, as long as the data allows for reasonable year-to-year comparisons and includes testing from non-prototype vehicles (85 FR 28148). We didn't receive any comments on the proposed changes to § 1037.665, and we are finalizing changes to the regulation as proposed. To qualify, the vehicles would need to be actual production vehicles rather than custom-built prototype vehicles. Such vehicles could be covered by testing or manufacturer owned exemptions but would need to be produced on an assembly line or other normal production practices. Manufacturers would also need to ensure test methods are sufficiently similar from year to year to allow for a meaningful analysis of trends.

6. Vehicle Model Year Definition

For Phase 2 tractors and vocational vehicles, the vehicle's regulatory model year is usually the calendar year corresponding to the vehicle's date of manufacture. However, the Phase 2 regulations allow the vehicle's model year to be designated as the year before the calendar year corresponding to the vehicle's date of manufacture if the engine's model year is from an earlier year. We are amending as proposed the definition of model year in § 1037.801 to allow vehicle manufacturers to extend the period during which a vehicle's certification is valid to account for this flexibility. This clarification more explicitly explains how vehicle manufacturers utilize this existing flexibility.

After promulgation of the Phase 2 final rule, it became apparent that the Phase 2 vehicle model year definition does not allow starting vehicle production before the start of the named year if the engine model year also begins in the earlier year. For example, if a manufacturer would start its 2024 engine model year in December 2023, the definition would not allow vehicles produced in 2023 to be model year 2024.

To address this issue, EPA is allowing the option for the vehicle's model year to be designated as the year after the calendar year corresponding to the vehicle's date of manufacture. This has the effect of allowing manufacturers to meet standards earlier with aligned engine and vehicle model years. Model years would still be constrained to reflect annual (rather than multi-year) production periods and include January 1 of the named year.

We did not receive comments on these proposed change to the definition of model year for vehicles. We are accordingly adopting the revised definition for model year in 40 CFR 1037.801 for tractors and vocational vehicles with a date of manufacture on or after January 1, 2021, as proposed, except that the final rule includes additional text to make explicit the requirement for the model year to be based on the manufacturer's annual production period for new models. This is consistent with the definition of model year for vehicles subject to Phase 1 standards in the same section.

7. Compliance Margins for GEM Inputs

The regulations at 40 CFR 1037.620(d) allow component manufacturers to conduct testing for vehicle manufacturers, but they do not specify restrictions for the format of the data. Vehicle manufacturers have raised concerns about component manufacturers including compliance margins in GEM inputs—in other words, inputting a value that is significantly worse than the tested result. They state that many component suppliers are providing GEM inputs with compliance margins, rather than raw test results. However, when stacked together, the compliance margins would result in inappropriately high GEM results that would not represent the vehicles being produced.

We proposed to note in 40 CFR 1037.501(i) that declared GEM inputs for fuel maps and aerodynamic drag area will typically include compliance margins to account for testing variability and that, for other measured GEM inputs, the declared values will typically be the measured values, and received comment requesting additional clarification and providing additional suggested revisions as described in Chapter 2 of the Response to Comments document. One commenter suggested that EPA finalize default allowance values at this time, however we lack adequate data to make a thorough determination on what these values should be. In addressing manufacturers' concern, it is important to distinguish between engine fuel maps (which are certified separately) and other GEM inputs that are not certified. As is discussed in Section II.B.3, certified engine fuel maps are expected to include compliance margins to account for manufacturing and test variability. However, EPA did not expect each of the other GEM input to have a significant compliance margin of its own. (Note that the aerodynamic bin structure serves to provide an inherent compliance margin for most vehicles.) Rather, we expected the certifying original equipment manufacturer (OEM) to include compliance margins in their Family Emission Limits (FELs) relative to the GEM outputs.

For vehicle GHG standards, the primary role for FEL compliance margins is to protect against SEA failures. Without a compliance margin under the Phase 2 regulations, normal production variability would cause some vehicles to fail, which would require the testing of additional vehicles. Even if the family ultimately passed the SEA, it would probably require the manufacturer to test a large number of vehicles. However, because SEAs and confirmatory tests for particular components would not target GEM inputs for other components, a modest vehicle FEL compliance margin determined by the vehicle manufacturer, that accounts for the component input with the highest uncertainty used to determine the vehicle FEL, would be sufficient to cover the full range of uncertainty for all components.

While we are not adopting explicit changes with respect to compliance margins that were requested in comments, we are finalizing the revision in § 1037.501(i) as with clarifying edits that, for other measured GEM inputs, the declared values are typically the measured values without adjustment, and finalizing a related provision after consideration of comments on this proposed revision and on conducting a confirmatory test and SEA for an axle or transmission apart from a specific vehicle. Specifically, the additional change clarifies this intent for confirmatory testing in 40 CFR 1037.235(c)(2) by stating that the results will only affect your vehicle FEL if the results of our confirmatory testing result in a GEM vehicle emission value that is higher than the vehicle FEL declared by the manufacturer.

These revisions further obviate a need for component-specific compliance margins and should thus further clarify that component-specific suppliers should be providing GEM inputs with raw test results, rather than values that include an associated compliance margin. While we do not believe that suppliers should normally include compliance margins when providing test data to OEMs for GEM inputs, we do believe they should provide to OEMs some characterization of the statistical confidence they have in their data. This allows the OEM to apply an appropriate overall compliance margin for their vehicle FEL. During a confirmatory test, EPA would compare the GEM results using our measured inputs with the declared FEL for the vehicles, which means that the compliance margin for measurement variability should be built into the FEL of the vehicle. Again, EPA notes that the certified engine fuel maps are expected to include small compliance margins to account for manufacturing and test variability.

Finally, none of this is intended to discourage suppliers and OEMs from entering into commercial agreements related to the accuracy of test results or SEA performance.

8. SEAs for Axles and Transmissions

Under 40 CFR 1037.320, a selective enforcement audit (SEA) for axles or transmissions would consist of performing measurements with a production axle or transmission to determine mean power loss values as declared for GEM simulations, and running GEM over one or more applicable duty cycles based on those measured values. The axle or transmission is considered passing for a given configuration if the new modeled emission result for every applicable duty cycle is at or below the modeled emission result corresponding to the declared GEM inputs. As described below, EPA is revising the provision regarding where an axle or transmission does not pass.

We believe special provisions are needed for axles and transmissions given their importance as compliance technologies and a market structure in which a single axle or transmission could be used by multiple certifying OEMs. Under the existing SEA regulations, if an axle or transmission family from an independent supplier fails a SEA, vehicle production could be disrupted for multiple OEMs and have serious economic impacts on them. We are finalizing a revision that will minimize the disruption to vehicle production.

Under the revised provision, if the initial axle or transmission passes, then the family would pass, and no further testing would be required. This is the same as under the existing regulations. However, if the initial axle or transmission does not pass, two additional production axles or transmissions, as applicable, would need to be tested. We are finalizing this revision as proposed, except we are finalizing additional changes to § 1037.320(c) after consideration of comments received to the proposal in a couple respects. We further clarified that these additional production axels or transmissions to be tested could be different axle and transmission configurations within the family to cover the range of product included in the family. We also are finalizing an additional clarification in 40 CFR 1037.320(c) that further address how the results from the SEA will be used to determine if the manufacturer declared map should be replaced, by stating that if you fail the audit test for any of the axles or transmissions tested, the audit result becomes the declared map, also requiring revision of any analytically derived maps if applicable, and that these would become official test results for the family. In other words, this approach would correct the data used by the OEM for their end-of-year report.

After consideration of comments, we are also finalizing changes to 40 CFR 1037.320(b) to clarify that the test transmission's gear ratios and not the default ratios in 40 CFR 1036.540 should be used in GEM. After consideration of comment regarding the lack of an engine defined for use as a GEM input when a component-level SEA is being performed, we have specified the use of the default engine map in 40 CFR part 1036, appendix C, and a default torque curve that we have added as Table 1 to 40 CFR 1037.520. The axle and transmission GEM inputs can now be determined based on the default map and torque curve. See Chapter 2 of the Response to Comments for further details on comments received and our responses.

9. Electric and Hybrid Vehicles in Vocational Applications

Prior to the proposal, manufacturers expressed concern that the Phase 2 regulations are not specific enough regarding how to classify hybrid vocational vehicles (see § 1037.140). This is not an issue for tractors, which are classified based on gross vehicle weight rating (GVWR). However, vocational vehicles are generally classified by the class of the engines. Obviously, this approach does not work for electric vehicle without engines. This approach could also misrepresent a hybrid vehicle that is able to use an undersized engine. To address these problems, we proposed changes to § 1037.140(g)(1) to clarify that the classification for tractors where provisions are the same as vocational vehicles applies for hybrid and non-hybrid vehicles, and paragraph (g)(4) to clarify that Class 8 hybrid and electric vehicles are Heavy HDVs and all other vehicles are classified by GVWR classes. CARB and Tesla supported the regulation changes proposed in § 1037.140(g). We did not receive any adverse comments on these proposed revisions and we are finalizing the proposed revisions with the addition of “electric” to paragraph (g)(1) for consistency with the rest of the section and an expanded clarification in paragraph (g)(4)(iii) that Class 8 hybrid and electric vehicles are considered Heavy HDV, regardless of the engine's primary intended service class.

CARB suggested tying certification provisions such as warranty and useful life to the vehicle GVWR to avoid allowing a downsized hybrid powertrain installed in a heavier vehicle weight class to have shorter useful life and emission warranty obligations. We note that useful life (§ 1037.105(e)) and warranty (§ 1037.120(b)) for vocational vehicles are defined by vehicle service class (i.e., Light HDV, Medium HDV, and Heavy HDV) and our final revision to § 1037.140(g)(4) ensures all Class 8 hybrid and electric vehicles are classified in our heaviest weight class with the longest useful life and warranty periods. Consequently, any powertrain in a Class 8 vehicle, including a downsized hybrid, would be a Heavy HDV and subject to all corresponding certification provisions for Heavy HDVs.

We also requested comment on alternative approaches, such as specifying the useful life in hours rather than miles for these vocational vehicles or allowing electric vehicles to step down one weight class, with justification from the manufacturer. With respect to the potential alternative approaches we requested comment on, Ford supported specifying useful life in hours rather than miles for vocational vehicles. However, CARB raised questions on how the useful life in miles correlates to engine hours. Tesla encouraged EPA to continue to use a single, miles-based criteria for useful life. In addition, Ford expressed support for allowing electric vehicles to step down one weight class. We are not taking final action on any of the potential alternative approaches at this time. Regarding adopting useful life criteria based on engine hours, we currently lack the data required to link engine hours to miles for the range of vocational vehicles. Regarding potentially allowing electric vehicles to step down one weight class, we currently have concerns that this may allow for inappropriate useful life and warranty requirements.

Section 1037.140(g)(5) references § 1037.106(f) in specifying that, in certain circumstances, you may certify vehicles to standards that apply for a different vehicle service class. We received comments from EMA and Volvo and agree with the commenters' suggestion to clarify how our revision to § 1037.140(g)(1) regarding hybrid and electric tractors interacts with the cross-referenced § 1037.106(f). Consistent with our explanation at proposal that the current requirements in § 1037.140(g) applied to all tractors, we are also finalizing a corresponding clarification in § 1037.106(f)(2) regarding Class 7 hybrid and electric tractor's ability to certify to the Class 8 standards, by adding a sentence that “[t]his applies equally for hybrid and electric vehicles.” See Chapter 2 of the Response to Comments for further details on comments received and our responses.

10. Vocational Vehicle Segmentation

The Phase 2 regulatory structure applies the primary vocational standards by subcategory. Manufacturers are generally allowed to certify vocational vehicles in the particular duty-cycle subcategory they believe to be most appropriate, consistent with good engineering judgment. This process for selecting the correct subcategory is often called “segmentation.” Under this structure, EPA expects manufacturers to choose a subcategory for each vehicle configuration that best represents the type of operation that vehicle will actually experience in use. This is important because several technologies provide very different emission reductions depending on the actual in-use drive cycle. For example, stop-start would provide the biggest emission reductions for urban vehicles and much less reduction for vehicles that operate primary on long intercity drives.

Vocational vehicles are classified based upon the gross vehicle weight rating (GVWR) as defined in § 1037.140(g). Once classified, manufacturers identify the intended regulatory subcategory duty cycles (i.e., Urban, Multi-purpose, or Regional) for each vocational vehicle configuration as indicated in § 1037.140(h). There are constraints for vocational duty cycle and regulatory subcategory, specified in § 1037.150(z).

Prior to the proposal, manufacturers raised concerns about the impact of this structure on their ability to plan for and monitor compliance. They suggested that more objective and quantitative “good engineering judgment” criteria would be helpful. In response to these concerns, EPA proposed an interim “safe harbor” provision in § 1037.150(bb) for vocational vehicle segmentation. Under the proposal, manufacturers meeting the safe harbor criteria would be presumed to have applied good engineering judgment, and we explained that we thought the criteria were consistent with the intent of the Phase 2 program and would not allow manufacturers to reduce the effective stringency the standards.

The first principle of the proposed safe harbor was that any vehicle could be classified as Multi-purpose. The Multi-purpose duty cycle weighting factors include significant weightings for highway operation, lower speed transient operation, and idle. Thus, it would not generally overvalue an individual technology. The second principle of the proposed safe harbor was that vehicles not classified as Multi-purpose should not be exclusively Regional or Urban. We proposed a quantitative measure that evaluates the ratio of Regional vehicles to Urban vehicles within an averaging set. Specifically, we proposed that the ratio of Regional vehicles to Urban vehicles must be between 1:5 and 5:1. EPA requested comment on the proposed approach overall and the range of acceptable ratios.

CARB supported the proposed provision of allowing any vocational vehicle to be classified as Multi-purpose. However, both EMA and CARB questioned the ratios for vocational vehicle categories in the proposed provisions of § 1037.150(bb). EMA commented that the proposed ratios were “arbitrary” and may not be represent a manufacturer's model mix during any specific year. Instead, EMA suggested that more appropriate “good engineering judgment” would be to base the vehicle category on “the duty cycle weighting under which it performs most efficiently in GEM.” CARB commented that the ratio could inadvertently drive manufacturers to certify the vehicles with an inappropriate duty cycle and recommended all vehicles be certified as Multi-purpose unless the manufacturer could provide “good justification” for a Regional or Urban categorization.

We are finalizing a revision in § 1037.140(h) and throughout § 1037.150(z) to replace “duty cycle” with the term “regulatory subcategory” that more appropriately reflects the intent of classifying a vehicle and its connection to a standard. Additionally, after considering the comments, EPA is finalizing one principle of the safe harbor provision proposed as § 1037.150(bb); specifically, the paragraph that allows manufacturers to select the Multi-purpose subcategory for any vocational vehicle, unless otherwise specified in § 1037.150(z). As noted previously, selecting this subcategory and associated duty cycle would require technologies that reduce emissions across all operation (i.e., high speed, lower speed transient, and idle) and we believe it is an appropriate default duty cycle if a manufacturer is unsure of the final vehicle application when applying the good engineering judgment provision of § 1037.140(h). We agree with the concerns expressed by CARB and EMA and are not finalizing the ratios of Regional to Urban vehicles in paragraph § 1037.150(bb)(2) of the proposed safe harbor provision. Instead, as discussed further below, we continue to rely on the constraints listed in § 1037.150(z) to guide manufacturers in identifying an appropriate duty cycle, with the addition of a Multi-purpose safe harbor.

Section 1037.150(z) outlines the constraints manufacturers apply when determining the appropriate vocational subcategory for their vehicles as described in § 1037.140. Instead of adding a new paragraph (bb) as proposed, we are reordering § 1037.150(z) and incorporating a new paragraph to allow the Multi-purpose classification. The modified § 1037.150(z)(1) through (3) now include the current provisions that identify the vehicle configurations (designed for higher-speed cruise operation) for which manufacturers must select the Regional subcategory, specifically if certified based solely on testing with the high-speed Supplemental Emission Test, if certified as a coach bus or motor home, or if equipped with a manual transmission after MY 2024. Except where one of those existing three criteria for the Regional subcategory apply, a new paragraph (z)(4) allows manufacturers to select the Multi-purpose subcategory for any vocational vehicle. The remaining renumbered paragraphs (z)(5) through (7) describe the current regulation's existing allowances for and limitations on selecting the Urban subcategory that are based on the most appropriate transmission configurations for lower speed, stop-and-go driving.

We continue to believe market forces will induce manufacturers to design their vocational vehicles such that their GHG emission performance (and fuel efficiency) is optimized for their customers' specific applications and, in most cases, it will be clear which subcategory and associated duty cycle is appropriate for a given vocational vehicle configuration. Consequently, the vehicles and their associated technology packages will also be relatively optimized for one of the vocational duty cycles available for compliance using GEM, as shown in Table 1 of § 1037.510. Where it is unclear, we would evaluate whether a manufacturer has applied the good engineering judgment required under § 1037.140(h) taking into consideration whether the subcategory selected is best suited for the vehicle as indicated by the totality of its powertrain options, vehicle features, and duty cycle performance under which it demonstrates the most favorable emissions result relative to the emission standard. We note that in our review of a manufacturer's good engineering judgment request, we reserve the right to require the use of a more appropriate duty cycle and subcategory. We will continue to monitor use of the good engineering judgment provision of § 1037.140(h) and the constraints listed in § 1037.150(z) and may re-evaluate our approach in the future if we determine it is necessary.

Thus, the final regulations include consideration of both EMA and CARB's suggestions. As noted previously, we would consider the duty cycle weighting under which the vehicle performs most efficiently in GEM in considering whether good engineering judgment was used, and have provided manufacturers of vehicles not subject to the constraints listed in § 1037.150(z) with a clear pathway to certify those vehicles as Multi-purpose if they are otherwise unable to justify Regional or Urban duty cycle when exercising good engineering judgment.

In the proposed rule, we also requested comment on the need for the subcategory on the label. EMA commented that it is unnecessary and a complication and burden for manufacturers to identify whether the vehicle is in the Urban, Multi-Purpose or Regional subcategory on the label and requested that we “remove the requirements in § 1037.135(c)(3) and (4)”. CARB commented and encouraged EPA to require the subcategory be on the label because it would help consumers choose the appropriate certified vehicles for their intended vehicle operation cycles. After consideration of EMA's and CARB's comments, we are removing the requirement to explicitly state the regulatory subcategory on the emission label as specified in § 1037.135(c)(4). In the Phase 2 final rulemaking, we concluded that it was unnecessary for the emission label to contain a comprehensive list of all emission components and that it is important to balance the manufacturers' “need to limit label content with the [the agencies'] interest in providing the most useful information for inspectors” (81 FR 73636, October 25, 2016). Since stating the regulatory subcategory on the label provides limited additional information inspectors could use to quickly determine if the vehicle is in its certified condition and the subcategory can be identified from the vehicle family name required by paragraph (c)(3), we believe it is appropriate to remove it as a requirement on the emission label. We are not revising the current requirement to print the standardized designation for the vehicle family name as required by § 1037.135(c)(3), which ensures consistency between the label and other compliance provisions that require the vehicle family name. As such, the regulatory subfamily can continue to be identified from the family name, which should help address CARB's concern if a consumer chooses to use the emissions label when deciding to purchase a vehicle.

11. Early Certification for Small Manufacturers

Vehicle manufacturers that qualify as small businesses are exempt from the Phase 1 standards, but must meet the Phase 2 standards beginning January 1, 2022. However, some vehicle families have been certified voluntarily to Phase 1 standards by small manufacturers. In an effort to encourage more voluntary early certification to Phase 1 standards, we proposed a new interim provision in § 1037.150(y)(4) for small manufacturers that certify their entire U.S.-directed production volume to the Phase 1 standards for calendar year 2021 (85 FR 28150). Small manufacturers may delay complying with the Phase 2 standards by one year, and instead comply with the Phase 1 standards for that year, if they voluntarily comply with the Phase 1 standards for one full prior year. Specifically, small manufacturers may certify their model year 2022 vehicles to the Phase 1 greenhouse gas standards of §§ 1037.105 and 1037.106 if they certify all the vehicles from their annual U.S.-directed production volume to the Phase 1 standards starting on or before January 1, 2021. If the small manufacturers do so, the provision allows these manufacturers to certify to the Phase 1 standards for model year 2022 (instead of the otherwise applicable Phase 2 standards). Early compliance with the Phase 1 standards should more than offset any reduction in benefits that would otherwise be achieved from meeting Phase 2 standards starting January 1, 2022.

The provision we proposed also allows the Phase 1 vehicle credits that small manufacturers generate from model year 2018 through 2022 vocational vehicles to be used through model year 2027. Under the existing regulations, all manufacturers that generate credits under the Phase 1 program are allowed to use such Phase 1 vehicle credits in the Phase 2 vehicle averaging, banking, and trading program, but the credits are subject to the five-year credit life. As noted in the proposed rule, we believe the limit on credit life can be problematic for small manufacturers with limited product lines which allow them less flexibility in averaging, and the longer credit life will provide them additional flexibility to ensure all their products are fully compliant by the time the Phase 2 standards are fully phased in for model year 2027. We note that these Phase 1 emission credits are based on the degree to which the Family Emission Limit is below the Phase 1 standard.

We received no adverse comment to either proposal for small manufacturers in § 1037.150(y)(4). Our final revisions include minor edits to the proposed credit-related provision in § 1037.150(y)(4) to create a standalone sentence and moving the proposed provision that describes the certification flexibility for these small manufacturers to a new § 1037.150(c)(4) where the applicable standards and implementation dates for qualifying small businesses are introduced.

12. Delegated Assembly

In 40 CFR 1037.621, EPA specifies provisions to allow manufacturers to ship incomplete vehicles and delegate the final assembly to another entity. Manufacturers previously expressed the concern that these “delegated assembly” requirements are too burdensome in some cases, particularly in cases such as auxiliary power units and natural gas fuel tanks. EPA requested comment on this issue and proposed a single clarifying edit in § 1037.621(g). CARB encouraged EPA to maintain the existing delegated assembly provisions. We received no comments adverse these existing provisions or providing suggestions for updated text. The final rule adopts only the single clarifying edit in § 1037.621(g), as proposed.

13. Canadian Vehicle Standards

During the Phase 2 rulemaking, Environment and Climate Change Canada (ECCC) emphasized that the highway weight limitations in Canada are much greater than those in the U.S. Where the U.S. Federal highways have limits of 80,000 pounds gross combined weight, Canadian provinces have weight limits up to 140,000 pounds. This difference could potentially limit emission reductions that could be achieved if ECCC were to fully harmonize with the U.S.'s HD Phase 2 standards because a significant portion of the tractors sold in Canada have GCWR (Gross Combined Weight Rating) greater than EPA's 120,000-pound weight criterion for “heavy-haul” tractors.

EPA addressed this in Phase 2 by adopting provisions that allow the manufacturers the option for vehicles above 120,000 pounds GCWR to meet the more stringent standards that reflect the ECCC views on appropriate technology improvements, along with the powertrain requirements that go along with higher GCWR (see 81 FR 73582, October 25, 2016). Vehicles in the 120,000 to 140,000 pound GCWR range would normally be treated as simple “heavy haul” tractors in GEM, which eliminates the GEM input for aerodynamics. However, vehicles certified to the optional standards would be classified as “heavy Class 8” tractors in GEM, which then requires an aerodynamic input. Nevertheless, they both use the heavier payload for heavy haul.

ECCC has since adopted final standards for these 120,000 to 140,000 pound GCWR tractors, which differ from the optional standards finalized in Phase 2. Since the purpose of these standards was to facilitate certification of vehicles intended for Canada, we proposed optional standards in § 1037.670 that would be the same as the final ECCC standards. We did not receive any comments adverse the proposed optional standards and we are finalizing the optional standards as proposed in § 1037.670. Note that these standards are not directly comparable to either the normal Class 8 standards or the heavy haul standards of § 1037.106 because GEM uses different inputs for them. Manufacturers who choose to opt into meeting the Canadian standards would achieve greater emission reductions compared to EPA's program.

ECCC has also adopted new standards for tractors in the 97,000 to 120,000 pound GCWR category. In general, EPA would classify a tractor in the 97,000 to 120,000 lb GCWR range in one of its Class 8 tractor subcategories. EPA's Class 8 tractor standards, which cover up to 120,000 lb GCWR, have standards that are more stringent than ECCC's standards for their 97,000 to 120,000 lb GCWR subcategory. We did not propose special provisions for these tractors, but requested comment on the need for special provisions for these vehicles. Both EMA and Volvo commented that special provisions are necessary to facilitate certification of 97,000 to 120,000-pound GCWR tractors for export to Canada. EMA suggested a similar approach for these 97,000 to 120,000-pound GCWR tractors as the one provided for the optional certification for tractors at or above 120,000 pounds GCWR, proposed in § 1037.670. Similarly, Volvo requested that EPA provide subcategories and standards for these tractors that align with the ECCC regulations. We have concerns with the suggestion of providing an option for tractor standards that are less stringent than our current standards. EPA did not propose and is not taking any final action on special provisions for such vehicles at this time.

14. Transmission Calibrations

Manufacturers with advanced transmission calibrations may use the powertrain test option in § 1037.550 to demonstrate the performance of their transmissions. We adopted this option to provide an incentive for the development of advanced transmissions with sophisticated calibrations.

Transmission manufacturers have developed some new efficient calibrations, but must also maintain less efficient calibrations to address special types of operation. Due to concerns about resale value, most customers want to retain the ability to select the correct calibration for their operation. For transmissions with such selectable calibrations, § 1037.235(a) requires that they test using the worst-case calibration, which can undermine the incentive to continue improving the calibrations. We received comment requesting that we allow averaging of the worst-case and best-case performance, however this request would be a significant departure from how engine families are certified and what 40 CFR part 1037 currently requires for transmissions. We also received comment on weighting the calibration performance based on the actual use of these calibrations in the field. We believe that this option will give the most representative use of these calibrations and their impact on CO₂ emissions. After consideration of these comments, we are finalizing a change to allow manufacturers to measure both the best- and worst-case calibrations and weight them by prior model year based on survey data, prior model year sales volume, or other appropriate means. This weighting will be accomplished by testing both calibrations and weighting the results in Table 2 of § 1037.550 as described in amendments made in § 1037.235(a). See Chapter 2 of the Response to Comments for further details on comments received and our responses.

15. Other Minor Heavy-Duty Vehicle Amendments

We received no adverse comments to the following proposed amendments. EPA is finalizing the following amendments to part 1037 as proposed:

• Section 1037.103(c)—Adding phrase “throughout the useful life”.
• Section 1037.105 Table 5—Updating footnote format in table.
• Section 1037.106 Table 1—Updating footnote format in table.
• Section 1037.120(b)—Correcting the text with respect to tires and Heavy Heavy-Duty vehicles.
• Section 1037.150(c)—Adding a sentence pointing to additional interim provisions for small manufacturers.
• Section 1037.150(aa)—Clarifying the production limit for drayage tractors under the custom chassis allowance.
• Section 1037.201(h)—Correcting phrase “except that § 1037.245 describes . . .” to refer to § 1037.243.
• Section 1037.205(e)—Correcting parenthetical “(see 40 CFR 1036.510)” to refer to 40 CFR 1036.503.
• Section 1037.225(e)—Reorganizing paragraph with the introduction noting starting data, paragraph (e)(1) with existing text, and a new paragraph (e)(2) regarding the requirement that the amended application be “correct and complete”.
• Section 1037.230(a)(2)—Adding two clarifying paragraphs for optional tractor subcategories.
• Section 1037.243(c)—Rephrasing for consistency with other paragraphs in the section.
• Section 1037.255—Replacing the possessive “your” with articles a/an/the throughout this section and added clarifying statements related to the information submitted in an application for a certificate of conformity.
• Section 1037.301(b)—Removing phrase “matches or exceeds the efficiency improvement”.
• Section 1037.635(c)(1)—Editorial, adding a missing “the”.
• Section 1037.701(h)—Editorial, fixing reference.
• Section 1037.705(c)(2)—Adding a clarification for exported vehicles.
• Section 1037.801—Correcting punctuation in Compression-ignition and Low rolling resistance tires definitions; adding the word “motor” to definition of Electric vehicle; adding definition of electronic control module; clarifying Heavy-duty vehicle definition with respect to incomplete vehicles; adding definition of High-strength steel; clarifying Light-duty truck definition; adding Tonne definition.
• Section 1037.805(c) and (d)—Editorial; updating to be consistent with format in other parts.

EPA is also finalizing the following additional amendments, that include revisions we are finalizing as proposed but with additional clarifications, editorial improvements, or to fix typographical errors, after consideration of comments, as noted. Chapter 2 of our Response to Comments includes additional details on some of these amendments, as well as other amendments or clarifications requested by commenters and our responses.

• Section 1037.150(c)—Reorganizing the section into subparagraphs; removing “qualifying” throughout; moving reference to NAICS codes into definition of “small manufacturer” in § 1037.801; and combining the statements regarding the MY 2022 implementation date for tractor and vocational vehicles and the additional delays in later years for alternatively-fueled tractors and vocational vehicles into the new paragraph (c)(2) to provide further clarification in response to CARB's seeming misinterpretation of the regulations in a submitted comment related to our proposed § 1037.150(y)(4) provision. Also moving the certification-focused portion of the early certification provision proposed as part of § 1037.150(y)(4) to a new paragraph (c)(4) as discussed in Section II.C.11.
• Section 1037.231(b)(7)—Adding an additional revision to provide clarification on forward gear availability, noting that available forward gear means the vehicle has the hardware and software to allow operation in those gears, consistent with our final revision to § 1037.520(g) as noted in Section II.A.2.
• Section 1037.235(h)—Providing an example of an “untested configuration” in response to EMA's request for clarification.
• Section 1037.601(a)(2)—Removing limit of “up to 50” and added a more general statement that we will limit the number of engines.
• Section 1037.615—Clarifying that fuel cells powered by hydrogen should have a Family Emission Limit of 0 g/ton-mile for calculating CO₂ credits. Vehicles fueled by hydrogen are inherently carbon-free, which supports treating these vehicles the same as electric vehicles. This clarification is responsive to a comment from EMA.
• Section 1037.660(a)(2)—Revising to specify the permissible delay before engaging neutral idle when the vehicle is stopped; updating from proposed value of two seconds to the final value of five seconds after consideration of a request from Ford that suggested “two seconds is too short to account for normal stops and restarts in real on-road driving”. This request was posed in an email to EPA following the proposed rule.

• Section 1037.740(b)—Updated naming convention to match vehicle service classes Our revised delay of five seconds for neutral idle accommodates Ford's request and is consistent with the permissible § 1037.740(b)—Updating the naming convention to match vehicle service classes.
• Section 1037.801—Updating the proposed definitions for “hybrid engine or powertrain” and “hybrid vehicle” to be consistent with the proposed and further developed hybrid powertrain test procedure revisions to part 1036, subpart F, and the definitions of “hybrid powertrain” and “mild hybrid” added to 40 CFR part 1036. These revisions add examples of systems that qualify as hybrid engines or powertrains, specifically systems that recover kinetic energy and use it to power an electric heater in the aftertreatment. Updating model year definition as discussed in Section II.C.6 and small manufacturer definition as discussed in II.C.11.
• Section 1037.805(b)—Updating quantity and quantity descriptions including additional revisions to those proposed to ensure that these descriptions were consistent throughout the part.
• Section 1037.805(f)—Adding an additional revision to those proposed to update gravitational constant after consideration of comments received on the proposal.
• Appendix III to part 1037—Updating the definition of the emission control identifier “DWSW” to clarify high-strength steel wheel and maintain consistency with the related requirements in Table 6 of § 1037.520, after consideration of comment by CARB.

D. Onboard Diagnostics (“OBD”)

EPA proposed several updates to the onboard diagnostic (OBD) provisions of 40 CFR part 86, subpart A, related to onboard diagnostic requirements for heavy-duty engines and requested comment on general improvements and efforts to harmonize EPA and CARB OBD requirements (see 85 FR 28152). This section presents the changes we are adopting to OBD requirements after consideration of comments received. Additional details on these and other OBD amendments or clarifications requested by commenters and our responses are available in Chapter 2 of our Response to Comments document.

EPA's OBD regulations for heavy-duty engines are contained in 40 CFR 86.010-18, and were promulgated February 24, 2009 (74 FR 8310). Although these regulations were originally harmonized with CARB's OBD program, CARB has since updated and made changes to their regulations which EPA has not adopted. Most recently, in October 2019, CARB approved revisions to the onboard diagnostics requirements that include implementation of real emissions assessment logging (REAL) for heavy-duty engines and other vehicles.

The proposed rule requested comment on differences between existing EPA and CARB OBD regulations and included specific proposed revisions intended to reduce these differences. EPA proposed six specific revisions to update existing OBD regulations and harmonize with CARB requirements. We received comments supportive of these proposals, as well as comments indicating that EPA should reconsider certain proposals to ensure the regulations are clear and have the desired effect. After further evaluation and consideration of comments, EPA is finalizing four of these six proposed revisions:

(1) Adopting as proposed the CARB 5% threshold for misfire in § 86.010-18(g)(2). This would allow manufacturers to not detect misfires under certain conditions, such as during aftertreatment regeneration and some low temperature operation.

(2) Adopting as proposed CARB's misfire flexibilities in 1971.1(e)(2.3.3) which include identifying when it is reasonable for a manufacturer to seek approval for systems that cannot detect all misfire under all required speed and load conditions and where they seek approval to disable misfire detections.

(3) Adopting with a clarification the proposed revision to our in-use compliance standards in § 86.010-18(p) to reflect the CARB approach for minimum ratios for representative samples where a system would be considered noncompliant if the representative test sample (or performance group) indicates that the in-use ratio is below 0.088. A clarification was added to specify that the in-use ratio is based on the “average” value for the test sample group.

(4) Adopting as proposed the allowance to use CARB OBD reporting templates for EPA OBD requirements.

EPA received comments on the 5% threshold for misfire indicating concern that the provision as proposed does not reflect CARB's most recent requirements. EPA's proposal in § 86.010-18(g)(2)(iii)(C) was to require misfire detection on those engines equipped with sensors that can detect misfire occurrences. Existing CARB requirements state that all diesel engines are required to continuously monitor for misfire, not just those engines equipped to detect for misfire. EPA is finalizing the misfire provision as proposed but may further review this provision and may consider harmonizing with existing CARB requirements that require misfire detection for all diesel engines as a part of a future rulemaking. For example, the Cleaner Trucks Initiative (“CTI”) rulemaking intends to consider updating existing EPA OBD regulations and harmonizing further with CARB OBD requirements as noted in the advance notice of proposed rulemaking (ANPR) (85 FR 3306, January 21, 2020). EPA received comment on the proposal to revise our in-use compliance standards that recommended adding a clarification to the proposed language to indicate that the in-use ratio is based on the average in-use ratio of the engines in the test sample group. The comment pointed out that the regulations as proposed were not clear as to how the in-use ratio would be determined. Existing EPA regulations in § 86.010-18(j)(3)(i) and (ii) specify that manufacturers must collect and report in-use monitoring performance data representative of production vehicles, separate production vehicles into monitoring performance groups and submit data that represents each of these groups. The purpose of this requirement is to analyze in-use data from more than one vehicle to ensure that the OBD system is functioning properly. The frequency that some OBD monitors run can vary depending on the duty cycle of a particular vehicle, therefore, using the average in-use ratio from to evaluate performance is most appropriate. Adding this clarification also increases the alignment of EPA and CARB OBD requirements. After consideration of these factors we have added the word “average” to § 86.010-18(p)(4)(ii) to provide this clarity. Comments were also received on the in-use requirements stating that an additional provision should be included to § 86.010-18(p)(4)(ii) to ensure that compliance with the in-use ratio requirement is not influenced by engines with very high ratios which could lower the average value. We are not finalizing this change at this time but intend to review whether or not revisions to this provision should be considered as a part of the CTI rulemaking effort. EPA received no adverse comments on the proposal to allow the use of CARB's OBD reporting template. Using the CARB template will help streamline certification processes and reduce the time manufacturers may spend entering duplicative information on different forms. EPA is finalizing this provision as proposed to help harmonize requirements and streamline the certification process.

EPA is not taking final action at this time on two proposed revisions: (1) To allow CARB certified configurations to not count as separate engines families for the purposes of determining OEM test requirements, and (2) to allow a simplified carryover OBD certification path intended for special engine families. We received comments indicating concern that these proposals were not clear. For example, CARB noted that the proposed regulatory requirements for both carryover certification and for determining required OBD demonstration testing requirements relied on the term “special engine family” which is not defined in EPA regulations. EPA intends to review these two issues and other comments received on existing OBD requirements as part of a more comprehensive effort to consider updating our existing OBD regulations in the intended CTI rulemaking.

II. Other Amendments

A. Ethanol-Blend Test Fuels for Nonroad Spark-Ignition Engines and Vehicles, Highway Motorcycles, and Portable Fuel Containers

EPA adopted exhaust and evaporative emission standards for gasoline-fueled nonroad engines, vehicles, and equipment before there was a Federal gasoline test fuel with 10 percent ethanol (E10). Most of those programs therefore relied on testing with neat gasoline (E0) or with a splash-blended mix of neat gasoline and ethanol to make E10. In the meantime, EPA adopted a Federal gasoline test fuel with 10 percent ethanol for testing motor vehicles (79 FR 23414, April 28, 2014).

California ARB adopted its own specification for an E10 test fuel for testing motor vehicles, referred to as “LEV III E10.” California ARB revised its nonroad emission control programs to require manufacturers to start using LEV III E10 test fuel for certification starting in model year 2020, without allowing for carryover of previous data from testing with neat gasoline. California ARB's move to require use of LEV III E10 test fuel for certification has led manufacturers to express a concern about the test burden associated with separate testing to demonstrate compliance with EPA and California ARB emission standards.

The concern for aligning test requirements related to test fuel applies for marine spark-ignition engines (40 CFR part 1045), nonroad spark-ignition engines above 19 kW (40 CFR part 1048), and recreational vehicles (40 CFR part 1051). We expect a similar situation to apply for highway motorcycles in the 2022-2025 time frame based on California ARB's plans for further rulemaking activity.

We have issued guidance for marine spark-ignition engines (40 CFR part 1045) and for recreational vehicles (40 CFR part 1051) describing how we may approve certification based on emission measurements with an E10 test fuel. We are revising 40 CFR parts 1045, 1048, and 1051, consistent with the recently issued guidance documents, to allow for certification based on emission measurements with EPA's E10 test fuel without requiring EPA approval, and without adjusting emission standards to account for fuel effects. For marine spark-ignition engines (40 CFR part 1045), this merely replaces the existing provision allowing for the alternative of using a splash-blended E10 test fuel. For recreational vehicles (40 CFR part 1051) and Large spark-ignition (Large SI) engines (40 CFR part 1048), naming EPA's E10 specification as the alternative test fuel is a new provision. We are not prepared in this rulemaking to justify adopting new emission standards or to otherwise change the stringency of the existing standards. It is therefore necessary for EPA to be able to do confirmatory testing with either the original E0 test fuel, or the manufacturer's selected alternative fuel.

We are also allowing the same approach for certification based on emission measurements with EPA's E10 test fuel for highway motorcycles (including EPA confirmatory testing with either E0 or E10).

We expect this approach of allowing E10 as an alternative test fuel to adequately address concerns for the identified sectors. Many of these engines have closed-loop fuel controls that reduce the effect of fuel variables on exhaust emissions. Many also have relatively large compliance margins relative to the standards that apply. These factors help manufacturers confidently test with E10 as an alternative fuel, knowing that they continue to be liable for meeting emission standards on the specified E0 test fuel.

In the proposed rule we described a process for approving the use of California ARB's LEV III E10 test fuel instead of EPA's E10 test fuel as the alternative test fuel. That process is detailed in the existing regulations at 40 CFR 1065.701(b). The National Marine Manufacturers Association, the Motorcycle Industry Council, and Polaris requested that we revise the regulation to include California ARB's LEV III E10 as an alternative test fuel. The two sets of fuel specifications are nearly identical, with the notable difference being that California ARB's LEV III E10 test fuel has a lower volatility, which corresponds to the fuel regulations that apply in California. For testing hot-stabilized engines, volatility has a very small effect on exhaust emissions.

We are not revising the regulation to specify California ARB's LEV III E10 test fuel as an alternative test fuel. We expect the approval process described in 40 CFR 1065.701(b) to allow for review that will typically result in approval to use the California test fuel. However, we remain concerned that there may be some limited circumstances in which testing with the California fuel may not be appropriate for EPA certification. For example, engine manufacturers might name a Family Emission Limit to earn emission credits with a very narrow compliance margin. In that case, we would want to be able to explore with the manufacturer whether its testing adequately supports the proposed application for certification. As another example, some nonroad sectors include standards and testing requirements for controlling off-cycle emissions. It may be appropriate for the manufacturer to perform some of this off-cycle testing for certification using EPA's E0 or E10 test fuel in addition to testing over specified duty cycles with California ARB's LEV III E10 test fuel. To illustrate this point, we observed from a recent experience exploring potential noncompliance that an engine that has electronic feedback control can have a sensitivity to fuel parameters that is much greater than we would expect based on a simple assessment of combustion chemistry. We also note that the experience of implementing these changes in test fuel requirements will inform our ongoing approach for approving requests. Data supporting the equivalence of EPA and California test fuels would lead us to reduce our concerns for approving requests. In contrast, if we learn that fuel effects are greater than expected, we would review requests more carefully. This more careful review could be limited to a single manufacturer or a single type of engine (or engine technology), or it may apply more broadly.

We specify evaporative emission standards and test procedures for portable fuel containers and nonroad spark-ignition equipment in 40 CFR part 59, subpart F, and 40 CFR part 1060, respectively. The gasoline test fuel is splash-blended E10. California ARB specifies their LEV III gasoline test fuel for the analogous procedures in California, but they allow manufacturers to submit data instead using EPA's specified test fuel. Accordingly, we believe manufacturers do not face the same burden of needing to perform duplicate measurements for the two agencies. We are therefore not changing the EPA test fuel for portable fuel containers.

Commenters largely affirmed the proposed approach for increased flexibility for using E10 test fuels. We understand this approach—allowing testing with E10 testing as an alternative procedure—to be an interim measure. We expect to continue the move toward adopting E10 test fuel specifications, without referencing an E0 test fuel specification, as we consider updating emission standards for each sector over time. When we establish new standards, we would expect to evaluate the stringency of those standards based on testing with E10 test fuel, which will allow for adopting a singular test fuel.

B. Removing Obsolete CFR Content

EPA first adopted emission standards for light-duty motor vehicles and heavy-duty highway engines in the 1970s. Emission standards for the first categories of nonroad engines started to apply in the 1990s. Each of these programs include emission standards that apply by model year. For most of these programs over time, engines and vehicles were subject to increasingly stringent standards and improved certification and testing requirements. All these standards and regulatory provisions are codified in the Code of Federal Regulations. As time passes, the regulations for past model years become obsolete, but it remains in print until there is a rulemaking change to remove it from print. We are removing large portions of this regulatory content that no longer applies. The following sections describe these changes for different sectors.

Note that Section III.D describes several amendments to emission control programs for motor vehicles in 40 CFR parts 85 and 86. These amendments include several provisions that also remove obsolete regulatory content.

1. Clean Fuel Fleet Standards (40 CFR Part 88)

The Clean Air Act Amendments of 1990 included numerical standards for the Clean Fuel Fleet program that were intended to encourage innovation and reduce emissions for fleets of motor vehicles in certain nonattainment areas as compared to conventionally fueled vehicles available at the time. As originally adopted, those Clean Fuel Fleet standards were substantially more stringent than the standards that applied to vehicles and engines generally.

Now that we have begun implementing Tier 3 standards in 40 CFR part 86, subpart S, the Clean Fuel Fleet standards are either less stringent than or equivalent to the standards that apply to vehicles and engines generally. Because the statute continues to require Clean Fuel Fleet standards for state clean-fuel vehicle programs, we cannot simply remove the Clean Fuel Fleet program from the regulations. Rather, we are implementing the Clean Fuel Fleet standards in 40 CFR part 88 with a compliance option where vehicles and engines certified to current standards under 40 CFR parts 86 and 1036 would be deemed to comply with the Clean Fuel Fleet standards as Ultra Low-Emission Vehicles. Further, the Clean Fuel Fleet program as adopted included labeling requirements for engine and vehicle manufacturers to identify compliant engines and vehicles, and a restriction against including such engines or vehicles when calculating emission credits. Both provisions would also no longer be applicable because of the earlier mentioned increased stringency of standards for engines and vehicles, and under the compliance option we are establishing. Therefore, we are also removing these regulations. This will give clear instructions to vehicle and engine manufacturers as well as states that continue to have Clean Fuel Fleet provisions in their State Implementation Plans or become subject to these requirements in the future under the Clean Air Act (CAA) sections 182(c)(4)(A) and 246(a).

For states with areas that become subject to the clean-fuel vehicle program requirements in the future based on a new designation as an ozone nonattainment area, the required state implementation plan submission for the program or for a substitute measure is due within 42 months after the effective date of an area's nonattainment designation. The clean-fuel vehicle program requirements apply for ozone nonattainment areas with an initial designation as Serious, Severe, or Extreme. For marginal and moderate ozone nonattainment areas that are reclassified as Serious, Severe, or Extreme, the required state implementation plan submission for the program or for a substitute measure is due on the date specified in the EPA rulemaking finalizing the area's reclassification.

The Clean Fuel Fleet program also depends on vehicle classifications that include Zero Emission Vehicles and Inherently Low-Emission Vehicles. We are therefore preserving these defined terms in 40 CFR part 88. Under the new provisions, we will consider as Zero Emission Vehicles all electric vehicles and any vehicle that does not emit NO_X, PM, HC, CO, or formaldehyde (including evaporative emissions). We are simplifying the definition of Inherently Low-Emission Vehicles to mean any certified vehicle that is designed to not vent fuel vapors to the atmosphere.

2. Legacy Nonroad Standards (40 CFR Parts 89 Through 94)

The 1990 amendments to the Clean Air Act authorized EPA to set emission standards for nonroad engines. This led to a series of rulemakings to adopt emission control programs for different nonroad sectors. From 1994 through 1999, EPA adopted these emission control programs in 40 CFR parts 89, 90, 91, 92, and 94 (all part of subchapter C).

Starting in 2002, EPA adopted emission standards for additional nonroad emission control programs in a new subchapter, which allowed for improved organization and harmonization across sectors. We codified these new standards and related provisions in 40 CFR parts 1048, 1051, 1065, and 1068 (all part of subchapter U). Since then, we have migrated the “legacy” emission control programs from subchapter C to subchapter U. In each case, the migration corresponded to new emission standards and substantially updated compliance and testing provisions. This applies for the following sectors:

As a result of this migration, engine manufacturers have not certified engines under the legacy parts for the last 5-10 years. Removing these legacy parts reduces the cost to the Agency and prevents confusion for readers who think that the old provisions still apply.

While EPA's engine certification programs don't rely on these obsolete provisions, the new programs refer to the legacy parts for some specific provisions. For example, the new standard-setting part for each type of engine/equipment allows manufacturers to continue to certify carryover engine families based on test data from procedures specified in the legacy parts. We are not discontinuing further use of carryover data from engines originally certified under the legacy parts. On the other hand, this provision will gradually sunset itself as manufacturers update engine designs and perform new testing for their engine families to meet current standards.

Another example of relying on the legacy parts in the new regulations is emission credits generated under the legacy parts. In most cases, current programs either disallow using those credits for certification, or they allow it without keeping separate accounts for credits generated under the legacy parts. We are making no changes where credits from legacy parts are either unavailable or indistinguishable from currently generated credits. One exception is for land-based nonroad diesel engines certified under 40 CFR parts 89 and 1039. Current provisions in § 1039.740 allow for limited use of Tier 2 and Tier 3 credits from part 89 for certifying Tier 4 engines. We are revising § 1039.740, as proposed, to continue to allow manufacturers to use credits generated from Tier 2 and Tier 3 engines by simply changing the relevant references 40 CFR part 89 to 40 CFR part 1039, appendix I.

We are also aware that other Federal and state regulations and compliance programs include numerous references to 40 CFR parts 89 through 94. To address this, we are replacing the full text of regulations in the legacy parts with a paragraph describing the historical scope and purpose for each part. The remaining paragraph also directs readers to the new regulations that apply in subchapter U and clarifies how the regulatory requirements transition to the new content. As an example, the statute and regulations prohibit tampering with certified engines throughout an engine's lifetime, even if the original text describing that prohibition no longer resides in its original location in the Code of Federal Regulations.

We are also including the emission standards from the legacy parts as reference material in an appendix in the appropriate CFR parts. This allows for readily citing the historical standards in our own emission control programs, and in any other Federal or state regulations or compliance materials that depend on citing emission standards that are no longer current for purposes of gaining EPA certification as part of our nonroad emission control program.

In addition to removing references to the legacy parts, we are taking the opportunity to remove additional obsolete content from the newer regulations. Most of these changes were adopted to address temporary concerns as part of transitioning to new standards or other new requirements. We adopted these changes in isolated regulatory sections as “interim provisions.” Most of these interim provisions have been obsolete for several years.

References to the legacy parts are especially common for stationary engines EPA regulates under 40 CFR part 60, subparts IIII and JJJJ. The emission standards for stationary engines in many cases rely on current or past nonroad emission standards in 40 CFR parts 89, 90, and 94. Including all the iterations of these emission standards as reference material allows us to preserve the existing set of standards and requirements for stationary engines. This rule includes numerous amendments to 40 CFR part 60 to change regulatory cites from the legacy parts to the new regulatory parts in subchapter U, or to copy referenced text directly into 40 CFR part 60.

Most of the changes for stationary engines in 40 CFR part 60 are intended to update references without changing standards or other provisions. We are making three more substantive changes. First, we are allowing all manufacturers of emergency stationary compression-ignition internal combustion engines and stationary emergency spark-ignition engines to certify using assigned deterioration factors. Since these emergency engines generally serve in standby status in anticipation of emergency situations, they often have lifetime operation that is much less extensive than non-emergency engines. Assigned deterioration factors would allow manufacturers to demonstrate the durability of emission controls without performing testing that might otherwise exceed the operating life of the engines being certified. We are prepared to publish assigned deterioration factors based on currently available information. We may need to revise those values in the future as additional information becomes available, so we are not including specific values for assigned deterioration factors in this rulemaking. We are adopting these provisions as proposed, except that we are referencing the relevant nonroad regulations that apply and we are clarifying that assigned deterioration factors for stationary engines are not limited to small-volume manufacturers.

Second, stationary spark-ignition engines are currently subject to emission standards and certification procedures adopted under 40 CFR part 90 for Phase 1 engines. Revising the requirements for these engines to instead rely on the certification procedures in 40 CFR part 1054 requires that we identify the Phase 1 standards as not including the following provisions that apply for Phase 3 engines (as noted in the amended regulatory text for appendix I of part 1054):

• The useful life and corresponding deterioration factors.
• Evaporative emission standards.
• Altitude adjustments.
• Warranty assurance provisions in § 1054.120(f).
• Emission-related installation instructions.
• Bonding.

Third, in response to a comment from the EMA, we are revising the instruction regarding VOC measurement methods to allow manufacturers to use any method that is specified for highway or nonroad engines in 40 CFR part 1065, subpart C. The current regulation at 40 CFR 60.4241(i) identifies specific measurement procedures. When we revised 40 CFR part 1065 to include fourier transform infrared analyzers as an additional measurement method, it would have been appropriate to modify 40 CFR 60.4241(i) to identify this additional measurement method. We are addressing that in this rule by broadly referencing test methods in 40 CFR part 1065, subpart C, which includes fourier transform infrared analyzers.

In addition, following the proposed rule, we realized that 40 CFR part 89 includes content that is, in fact, not obsolete. Specifically, there is an interpretation of the Clean Air Act regarding the preemption of state regulations related to nonroad engines in 40 CFR part 89, subpart A, appendix A (62 FR 67736, December 30, 1997). This interpretation describes EPA's belief that states may regulate the use and operation of nonroad engines within certain parameters. This final rule preserves appendix A by copying it into 40 CFR part 1074, where we more broadly describe a range of issues related to preemption of state regulation of nonroad engines.

C. Certification Fees (40 CFR Part 1027)

EPA is making several minor changes in 40 CFR part 1027 to update the procedures and align the instructions with current practices. None of these changes involve change or reconsideration of fee policies. We are finalizing the following changes:

• Correcting the name of the compliance program.
• Replacing the schedule of fees from 2005 with the fees that apply for applications submitted in 2020.
• Revising the timeline for announcing adjusted fees for the upcoming year from a January 31 deadline to a March 31 deadline. This will allow for a more orderly process of calculating the new fees using the information from the previous year.
• Correcting the equation for non-evaporative certificates to no longer apply the inflation adjustment to operating costs. This corrects a publishing error that mistakenly introduced parentheses in the equation.
• Correcting the internet address for the consumer price index used for inflation adjustments.
• Removing the sample calculation for determining fees for 2006.
• Revising submission and payment instructions to refer only to electronic forms and transactions through www.Pay.gov.
• Clarifying that deficient filings must be resolved before the end of the model year, and that the time limit for requesting refunds applies equally to deficient filings.

We received no comments on the proposed amendments to 40 CFR part 1027 and are adopting these amendments without modification.

D. Additional Amendments for Motor Vehicles and Motor Vehicle Engines (40 CFR Parts 85 and 86)

Motor vehicles and motor vehicle engines are subject to emission standards and certification requirements under 40 CFR part 86. This applies for light-duty vehicles, light-duty trucks, heavy-duty vehicles and engines, and highway motorcycles. There are additional compliance provisions in 40 CFR part 85. We are adopting the following amendments to these provisions:

Part 85: We are amending the provisions for importation, exemptions, and model year to clarify that they no longer apply for heavy-duty engines. Those engines are already subject to analogous provisions under 40 CFR part 1068. While the two sets of provisions are largely the same, we want to avoid the ambiguity of having overlapping requirements. One aspect of this migration involves discontinuing the provisions that apply for Independent Commercial Importers for heavy-duty engines. No one has used these provisions for several years, and we have no reason to believe anyone will start to use these provisions. We are revising the regulatory text for the final rule, based on a comment, to clarify that the importation provisions continue to apply for highway motorcycles, and that references to engines in 40 CFR part 85, subpart P, continue to apply for replacement engines intended for installation in motor vehicles subject to the same importation provisions.

Part 85: We are making several minor corrections to (1) refer to provisions in 40 CFR part 1068 related to confidential business information and hearing procedures, and (2) clarify organization names and addresses for submitting information.

Part 85, subpart O: This subpart set emission standards for 1993 and older model year urban buses undergoing engine rebuilding. We have confirmed with the American Public Transportation Association that there are very few such urban buses still operating, and that none of them will have engine rebuilds. We are therefore removing this content from the CFR.

Section 85.1902(b)(2): We are clarifying that defect-reporting requirements under paragraph (b)(2) apply for defects related to noncompliance with greenhouse gas emission standards, not criteria emission standards. This corrects an earlier amendment that inadvertently described the provisions as applying to noncompliance with any kind of emission standard. Defects related to criteria emission standards are covered by § 85.1902(b)(1).

Sections 86.113-04, 86.213, and 86.513: Adding optional reference procedures for measuring aromatic and olefin content of E0 gasoline test fuel. These changes align with the reference procedures for EPA's Tier 3 E10 gasoline test fuel at 40 CFR 1065.710(b). These changes are needed because material limitations prevent laboratories from using the procedures in ASTM D1319. This change also applies for the E0 gasoline test fuel specified in 40 CFR 1065.710(c),

Section 86.129-00: Revising the description of test weight basis to be loaded vehicle weight for all light-duty vehicles and light-duty trucks. This is a correction to align the regulation with current practice.

Section 86.130-96: We are correcting the reference to a testing flowchart that was moved to 40 CFR 1066.801.

Sections 86.401-97 and 86.413-78: We are removing obsolete sections to prevent confusion.

Sections 86.419-2006 and 86.427-78: We are revising the table with service accumulation parameters to clarify how to perform testing separately for Class I-A and Class I-B, rather than treating them as a single class.

Sections 86.435-78 and 86.436-78: We are correcting references to the regulation to clarify that a motorcycle is compliant if measured test results are at or below the standards.

Section 86.531-78: We are adding instruction to seal exhaust system leaks as needed before testing highway motorcycles. The amendment also applies for testing off-highway motorcycles and all-terrain vehicles under 40 CFR part 1051. This same instruction also applies for light-duty vehicle testing under 40 CFR 1066.110(b)(1)(vi). We made minor wording changes after the proposed rule to clarify that manufacturers need to close all known leaks as part of the effort to prevent exhaust leaks from affecting the compliance demonstration.

Part 86, subpart P: The idle test procedures for spark-ignition engine and vehicles are no longer needed for certification or other compliance demonstrations. We are therefore removing this content from the CFR.

Part 86, subpart Q: Engine technology has advanced to include internal feedback controls and compensation to allow for operation at a wide range of altitudes. The certification requirements related to altitude adjustments are therefore mostly or completely obsolete. We are finalizing a simplified version of the altitude provisions for highway motorcycles at 40 CFR 86.408-78(c) and (d) in case there are some very small motorcycles that require adjustment for altitude.

Section 86.1803-01: We are revising the definition for heavy-duty vehicle, with a conforming revision to the definition for light-duty truck, to clarify that the sole regulatory criterion for whether a complete vehicle is a heavy-duty vehicle for purposes of the regulation is whether its gross vehicle weight rating is above 8,500 pounds. The current approach remains unchanged for incomplete vehicles; that is, heavy-duty vehicles also include incomplete vehicles even if their gross vehicle weight rating is at or below 8,500 pounds, if their curb weight is above 6,000 pounds or if their basic vehicle frontal area is greater than 45 square feet. The revisions are intended to (1) prevent light-duty trucks from becoming heavy-duty vehicles in a configuration involving a hybrid powertrain due to the extra weight related to energy storage and (2) avoid an incentive for manufacturers to add vehicle weight or frontal area simply to avoid the standards that apply for light-duty vehicles. In these cases, under the current definition, the curb weight or frontal area would artificially increase to the point that the vehicle would qualify as a heavy-duty vehicle, even though it otherwise has the characteristics of a light-duty truck. This same change is not necessary for incomplete vehicles because certifying manufacturers have the option to select the appropriate vehicle classification for those vehicles. Note that the change applies only for future certification; any certified heavy-duty vehicle that would no longer fit the description will not be affected by the amended definition.

Section 86.1811-17: The Federal Register mistakenly published a reference to the Tier 3 p.m. standard. Since we intended for the standard to apply at all times, we are amending the regulation to properly refer to that as the Tier 3 p.m. standard.

Section 86.1813-01: We are clarifying that electric vehicles and fuel cell vehicles are not subject to evaporative and refueling emission standards. The preamble to the final rule adopting the light-duty Tier 3 standards stated that these emission standards apply only for volatile fuels, but we did not include a clear statement excluding electric vehicles and fuel cell vehicles in the regulations (79 FR 23514, April 28, 2014).

Section 86.1818-12: We are clarifying that manufacturers calculate the in-use CO2 standard using the appropriate test result for carbon-related exhaust emissions after adjustment with the deterioration factor to account for durability effects. In many cases, the deterioration factor is 0 (additive) or 1 (multiplicative), in which case the deterioration factor does not change the calculated in-use CO2 standard.

Section 86.1838-01: We are restoring text that was inadvertently removed in an earlier amendment. The restored text specifies which mileage provisions from § 86.1845 do not apply for small-volume manufacturers doing in-use verification testing.

Section 86.1868: We are adopting detailed provisions describing how reduced air conditioning test requirements apply for electric vehicles and plug-in hybrid electric vehicles. These provisions are consistent with current practice described in EPA guidance. We specify that plug-in hybrid electric vehicles qualify for relief from AC17 testing, like electric vehicles, if they have an adjusted all electric range of 60 miles or more and they do not need engine power for cabin cooling during vehicle operation represented by the AC17 procedure; in response to a comment on the proposed rule, we have revised the amended regulatory text to clarify that the specified driving range applies for combined city/highway driving. Specifying a 60-mile range is intended to include vehicles for which an owner can typically expect to avoid using the engine for daily commuting, including commutes on a hot summer day. Finally, we are clarifying that manufacturers do not need to make a demonstration to qualify for air conditioning efficiency credits for pure electric vehicles or for plug-in hybrid electric vehicles, provided that those vehicles qualify for waived AC17 testing as described above. This is due to the complexity of quantifying credit quantities in grams CO2 per mile for driving without engine power. We also specify that AC17 testing with plug-in hybrid electric vehicles, if required, always be done in charge-sustaining mode to avoid the confounding effect of intermittent engine operation during the test.

E. Additional Amendments for Locomotives (40 CFR Part 1033)

EPA is updating 40 CFR part 1033 to remove references to specific content in 40 CFR part 92, as described in Section III.B.2. In addition, we are adopting the following minor corrections and changes:

Section 1033.150: Remove the interim provisions that no longer apply. This leaves paragraphs (e) and (k) as the only remaining paragraphs in this section.

Section 1033.255: Clarify that doing anything to make information false or incomplete after submitting an application for certification is the same as submitting false or incomplete information. For example, if there is a change to any corporate information or engine parameters described in the manufacturer's previously submitted application for certification, the manufacturer must amend the application to include the new information. Amendments include additional minor changes to align regulatory text across programs.

Section 1033.601: Correct references to specific provisions in 40 CFR part 1068.

Section 1033.701: Correct a paragraph reference.

Section 1033.740: Remove the reference to part 92 because the emission credit provisions of part 92 are being removed from the CFR. We are replacing the reference to emission credits from part 92 with the equivalent statement saying that manufacturers may continue to use emission credits from locomotives certified in 2008 and earlier model years. EPA's recordkeeping will not identify credits as being from either part 92 or 1033. Any credits generated under part 92 will continue to be available for certifying locomotives under part 1033.

Section 1033.901: Name the date, January 1, 2000, that marked the start of the original locomotive emission standards, rather than describing the date with reference to publication of the original final rule and its effective date (18978 FR 63, April 16, 1998).

Section 1033.925: Removing text in paragraph (e) that is already in paragraph (b) of the same section.

F. Additional Amendments for Land-Based Nonroad Diesel Engines (40 CFR Part 1039)

EPA's emission standards and certification requirements for land-based nonroad compression-ignition (CI) engines are identified in 40 CFR part 1039. We refer to these as Nonroad CI engines. Several changes to 40 CFR part 1039 that apply broadly are described above. Specifically, Section III.B.2 describes how we are removing regulatory content related to the Tier 1, Tier 2, and Tier 3 standards originally adopted in 40 CFR part 89. We are accordingly amending 40 CFR part 1039 to remove references to 40 CFR part 89 that no longer apply.

This section describes additional amendments for EPA's Nonroad CI program:

Section 1039.20: Remove the option to use a branded name instead of the engine manufacturer's corporate name for uncertified stationary engines. Since these engines are not certified, there is no way for EPA to document any relationship between the engine manufacturer and the branded company. We also are not aware of anyone using this provision.

Section 1039.20: Revise the label statement for stationary engines covered by § 1039.20 to avoid references to specific parts of the CFR. This is intended to prevent confusion. We can approve continued use of labels with the older previous statement under the provisions of § 1039.135(f). This may be needed, for example, if manufacturers have remaining labels in their inventory.

Section 1039.101: Add a table entry to clarify how standards apply for engines with maximum engine power above 560 kW. The current rendering in the Code of Federal Regulations can be misleading.

Section 1039.102: Correct the heading of Table 6 to include engines at or below 560 kW. The table was published in a way that inadvertently excluded 560 kW engines.

Section 1039.135: Discontinue the equipment labeling requirement to state that engines must be refueled with ultra low-sulfur diesel fuel (ULSD). Since in-use diesel fuel for these engines must universally meet ULSD requirements, there is no longer a benefit to including this label information.

Section 1039.205: Add text to clarify how engine manufacturers should identify information in the application for certification related to engine diagnostic systems that are required under § 1039.110.

Section 1039.255: Clarify that doing anything to make information false or incomplete after submitting an application for certification is the same as submitting false or incomplete information. For example, if there is a change to any corporate information or engine parameters described in the manufacturer's previously submitted application for certification, the manufacturer must amend the application to include the new information. Amendments include additional minor changes to align regulatory text across programs.

Section 1039.740: Remove the reference to emission credits from part 89. There is no need for this since the records related to credit accounting do not identify credits as being from part 89 or 1039.

• Section 1039.801: Revise the definition of “low-hour” to state that engines with NO_X aftertreatment should qualify as “low-hour” up to 300 hours, with other engines qualifying as “low-hour” up to only 125 hours. This is intended to ensure that engines tested to establish the low-hour emission result for an engine family are properly represented as new engines that have not started to experience deterioration of emission controls. In line with the comments from EMA, we understand the longer stabilization period to be appropriate for engines with NO_X aftertreatment. In contrast, engines without NO_X aftertreatment reach a point of stabilized emission levels much sooner, which supports the shorter duration for low-hour testing before starting service accumulation. This does not preclude continued testing beyond 125 hours for engines without NO_X aftertreatment, but it would prevent manufacturers from planning test programs that extend well beyond 125 hours. This is similar to provisions that already apply for marine diesel engines under 40 CFR part 1042; however, we are also adjusting the definition of “low-hour” for marine diesel engines to reference NO_X aftertreatment instead of a power cutoff.
• Section 1039.801: Revise the definition of “small-volume engine manufacturer” to remove the requirement to have certified engines in the United States before 2003. This limitation was related to the transition to meeting the Tier 4 standards. Now that those phase-in provisions have expired, the remaining provisions relate to reporting CH₄ and N₂ O emissions and using assigned deterioration factors. We believe these provisions can reasonably be applied to start-up small businesses meeting the Tier 4 standards.

G. Additional Amendments for Marine Diesel Engines (40 CFR Parts 1042 and 1043)

EPA's emission standards and certification requirements for marine diesel engines under the Clean Air Act are set out in 40 CFR part 1042. Emission standards and related fuel requirements that apply internationally are set out in 40 CFR part 1043.

Several changes to 40 CFR part 1042 that apply more broadly are described above. Specifically, Section III.B.2 describes how we are removing regulatory content related to the Tier 1 and Tier 2 standards originally adopted in 40 CFR part 94. We are accordingly amending 40 CFR part 1042 to remove references to 40 CFR part 94 that no longer apply.

This section describes additional amendments for our marine diesel engine program.

1. Marine Replacement Engine Exemption

We are adopting several adjustments to the replacement engine exemption in § 1042.615.

a. EPA's Advance Determination for Tier 4 Marine Replacement Engines

The proposed rule described that we were intending to clarify the regulatory determination that applies for cases involving new replacement engines that are normally subject to Tier 4 standards (see § 1042.615(a)(1)). In the 2008 final rule to adopt the Tier 4 standards, we finalized a determination “that Tier 4 engines equipped with aftertreatment technology to control either NO_X or PM are not required for use as replacement engines for engines from previous tiers in accordance with this regulatory replacement engine provision.” The preamble to that final rule made it clear that the determination was limited to “Tier 4 marine diesel replacement engines that comply with the Tier 4 standards through the use of catalytic aftertreatment systems.” (73 FR 37157) However, that limitation was not copied into the regulatory text. The development involving Tier 4 engines that rely on exhaust gas recirculation (EGR) instead of aftertreatment led us to revisit the discrepancy from the 2008 rule. The 2008 rule also stated that “[s]hould an engine manufacturer develop a Tier 4 compliant engine solution that does not require the use of such technology, then this automatic determination will not apply.”

EMA and the California Air Resources Board (CARB) both commented on the proposed change to the replacement engine exemption in § 1042.615(a)(1). EMA's comment suggested that we should leave the regulatory text in § 1042.615(a)(1) unchanged from what we adopted in 2008. CARB suggested that we entirely abandon the advance determination that Tier 4 engines are not suitable as replacements for earlier engines, regardless of aftertreatment, which would require a case-by-case engineering analysis in all cases to demonstrate that an exemption is appropriate.

As we explained in the 2008 rulemaking, an engine manufacturer is generally prohibited from selling a marine engine that does not meet the standards that are in effect when that engine is produced. However, we recognized that there may be situations in which a vessel owner may require an engine certified to an earlier tier of standards, including (1) when a vessel has been designed to use a particular engine such that it cannot physically accommodate a different engine due to size or weight constraints (e.g., a new engine model will not fit into the existing engine compartment); or (2) when the engine is matched to key vessel components such as the propeller, or when a vessel has a pair of engines that must be matched for the vessel to function properly. Our 2008 rule allows the engine manufacturer to make the relevant determinations, but we adopted a provision that requires the engine manufacturer to consider all previous tiers and use any of their own engine models from the most recent tier that meets the vessel's physical and performance requirements. If an engine manufacturer produces an engine that meets a previous tier of standards representing better control of emissions than that of the engine being replaced, the manufacturer would need to supply the engine meeting the tier of standards with the lowest emission levels.

At that time, we made an advance determination that Tier 4 engines would not be required as replacement engines for previous tier engines. As we explained in Section IV.C.2 of the final rule preamble, we expected that installing such a Tier 4 engine in a vessel that was originally designed and built with a previous tier engine could require extensive vessel modifications (e.g., addition of a urea tank and associated plumbing; extra room for a SCR or PM filter; additional control equipment) that may affect important vessel characteristics such as vessel stability. We stated that we were not implying Tier 4 engines would never be appropriate as replacements for engines from previous tiers; rather, the determination was intended to simplify the search across engines and was based on the presumption that Tier 4 engines would not fit in most cases. We also stated that the advance determination was made solely for Tier 4 marine diesel replacement engines that comply with the Tier 4 standards through the use of catalytic aftertreatment systems. We stated: “Should an engine manufacturer develop a Tier 4 compliant engine solution that does not require the use of such technology, then this automatic determination will not apply. Instead our existing provision will apply and it would be necessary to show that a non-catalytic Tier 4 engine would not meet the required physical or performance needs of the vessel.”

We were also not intending to prevent states or local entities from including Tier 4 engines in incentive programs that encourage vessel owners to replace existing previous tier engines with new Tier 4 engines or to retrofit control technologies on existing engines, since those incentive programs often are designed to offset some of the costs of installing or using advanced emission control technology solutions. However, on a national basis, we continue to believe our original approach described in the 2008 final rule is appropriate. The characteristics of the national fleet are likely different from the fleet of vessels affected in California; taking away the Tier 4 determination should not be made lightly or without a thorough understanding of the impact on existing boats. It would therefore be appropriate for us to include the advance determination that Tier 4 engines with aftertreatment are not suitable as replacement for earlier engines. In particular, we stand by our 2008 assessment that it is appropriate to automatically consider SCR-equipped engines to not have “the appropriate physical or performance characteristics to repower” pre-Tier 4 vessels, which in turn qualifies the repower for an exempt replacement engine.

EMA objected to the proposed clarification to apply the advance determination only for engines that meet Tier 4 standards with aftertreatment. The EMA comment suggests that the same presumption and regulatory burden should apply for EGR-equipped engines because compliant engines with EGR instead of aftertreatment also necessarily involve significant costs and vessel redesigns. EGR-equipped engines use exhaust gas recirculation (EGR) instead of SCR to control NO_X emissions. Engines with EGR include additional hardware to manage airflow in and through the engine, and to manage wastewater.

Revising the regulation to make clear that the advance determination was not intended to include EGR-equipped engines from the advance determination is in fact a very minor change in policy. Engine manufacturers may still qualify for the replacement engine exemption based on a showing that an EGR-equipped engine does not have “the appropriate physical or performance characteristics to repower the vessel.” However, there are two reasons to believe that EGR-equipped engines may be suitable for repower. First, all EGR-equipped Tier 4 engines are locomotive-sized Category 2 engines. Vessels with Category 2 engines generally have engine compartments that have room for additional hardware and other componentry. Second, the additional hardware for EGR-equipped engines would generally involve a greater design effort than upgrading to a Tier 3 engine, but this kind of change would often fit within the scope of vessel repower projects. Vessel owners would also need to follow new protocols for maintaining the engines and dealing with wastewater and other technical issues. None of these challenges create any inherent conflict with installing the Tier 4 engines to replace earlier engines.

These factors together support a policy in which an EGR-equipped engine can be considered unsuitable for repower based on its physical or performance characteristics, but this conclusion should not be presumed. We would accomplish that policy objective by revising § 1042.615(a)(1) as proposed.

b. Other Amendments Related to Marine Replacement Engines

We are modifying the requirement that engine manufacturers notify EPA after shipping exempt replacement engines. As originally adopted, § 1042.615(a) requires an engine manufacturer to send EPA notification 30 days after shipping an exempt engine to demonstrate that the selected engine was the cleanest available for the given installation. We indicated that “[t]hese records will be used by EPA to evaluate whether engine manufacturers are properly making the feasibility determination and applying the replacement engine provisions.” We also indicated that we expected engine manufacturers to examine “not just engine dimensions and weight but other pertinent vessel characteristics such as drive shafts, reduction gears, cooling systems, exhaust and ventilation systems, and propeller shafts; electrical systems; . . . and such other ancillary systems and vessel equipment that would affect the choice of an engine.” While engine manufacturers have submitted these reports, the information provided has not supported our original objective. Specifically, the reports vary widely in information provided but in many instances are too case-specific. Therefore, we are requiring manufacturers to submit a single annual report that is due at the same time as the general requirement for reporting on replacement engines under 40 CFR 1068.240. The annual report would include the information described in our 2008 rule for all the affected engines and vessels. This change would provide a predictable schedule for EPA to review the submitted information. This would also allow EPA to standardize the format and substance of the reported information. Manufacturers would benefit from submitting a consistent set of information in an annual submission for all their replacement engine information.

We are revising the regulatory instructions for submitting replacement engine reports under § 1042.615. The replacement engine exemption applies only for engines that are shipped to boat owners or are otherwise designated for a specific vessel. Engine manufacturers may produce and ship exempt replacement engines (with per-cylinder displacement up to 7 liters) without making the specified demonstrations, as allowed under 40 CFR 1068.240(c), but manufacturers may produce only a limited number of those “untracked” engines in a given year. Those untracked replacement engines are covered by the reporting requirements that apply under § 1068.240 since the tracked exemption under §§ 1042.615 and 1068.240(b) does not allow for shipping engines to distributors without identifying a specific installation and making the necessary demonstrations for that installation. We are taking a streamlined approach for reporting related to Tier 3 engines since the demonstration for those engines consists of affirming EPA's regulatory determination that no suitable Tier 4 engines (without aftertreatment) are available for replacement. We do not expect engines with per-cylinder engine displacement below 7 liters to be able to meet Tier 4 standards without aftertreatment devices. As a result, Tier 3 replacement engines are limited only in that they may not be used to replace engines that were certified to Tier 4 standards.

Finally, we are clarifying that the determination related to Tier 4 replacement engines applies differently for engines that become new based on vessel modifications. Under the definition of “new vessel” in § 1042.901, modification of an existing vessel may cause the vessel to become “new” if the vessel modifications cause the vessel's assessed value to at least double. In this case, all engines installed on the vessel are subject to standards for the model year based on the date of vessel modifications. Since the effective dates of the Tier 4 standards, we have learned that there may be circumstances in which vessel modifications may be substantial enough to qualify a vessel as “new,” but the installation of new Tier 4 engines may not be practical or feasible without cost-prohibitive additional vessel modifications. For example, a commercial vessel owner may want to substantially upgrade an older vessel, including engine replacement with a much lower-emitting engine. If the upgrade doubles the assessed value of the vessel, this would trigger a need for all installed or replacement engines above 600 kW to be certified to Tier 4 standards. We have learned that such a project may become cost-prohibitive based on the additional vessel modifications needed to accommodate the Tier 4 engine, which could cause the vessel to continue operating in the higher-emitting configuration. To address this scenario, we are allowing the replacement engine exemption for certain vessels that become new because of modifications, subject to a set of conditions. Specifically, the exemption would apply only with EPA's advance approval based on a demonstration that the installation of a Tier 4 engine would require significant vessel redesign that is infeasible or impractical. EPA's assessment may account for the extent of the modifications already planned for the project. EPA may approve installation of Tier 3 engines instead of Tier 4 engines for qualifying vessels. Recreational engines and commercial engines below 600 kW are not subject to Tier 4 standards. As a result, if a vessel becomes new through modification, it should be reasonable to expect such new engines to be certified to Tier 3 standards rather than being eligible for the replacement engine exemption.

2. Provisions Related to On-Off Controls for Marine Engines

EPA adopted the current set of emissions standards for Category 3 marine diesel engines in 2010 (75 FR 22932; April 30, 2010). The Tier 3 standards include provisions allowing engine manufacturers to design their engines with control systems that allow an engine to meet the Tier 3 standards while operating in U.S. waters, including the North American Emission Control Area and the U.S. Caribbean Sea Emission Control Area (ECAs), and the less stringent Tier 2 standards while operating outside of U.S. waters. We refer to this design strategy as “on-off control.” These provisions reflect the geographic nature of the NO_X engine standards contained in Regulation 13, MARPOL Annex VI.

Engine manufacturers have raised questions about the meaning of the regulatory provision at § 1042.101 that requires Category 3 engines to “comply fully with the Tier 2 standards when the Tier 3 emission controls are disabled.” This was intended to incorporate the “on-off controls” allowed under MARPOL Annex VI for the IMO Tier III NO_X limits. The HC and CO standards for Category 3 engines apply equally for EPA's Tier 2 and Tier 3 standards adopted under the Clean Air Act, so there should be no question that those standards apply even if NO_X controls are disabled. While 40 CFR 1042.104 includes a PM requirement, it is a reporting requirement only. The only other “standard” for Category 3 engines in 40 CFR part 1042 is the requirement related to mode caps in § 1042.104(c). The mode caps serve as separate emission standards for each test point in the duty cycle used for certifying the engines. The 2010 final rule describes how the mode caps are necessary for proper implementation of the Tier 3 standards for SCR-equipped engines (75 FR 22932). Since Category 3 engines with SCR systems would generally comply with the Tier 2 NO_X standard in the “disabled” configuration without SCR, we believe there would be no benefit to applying the mode caps as a part of the Tier 2 configuration for these Tier 3 engines with on-off controls. We are therefore clarifying that the mode caps are associated only with the Tier 3 NO_X standards. This approach is consistent with the on-off control provisions adopted under MARPOL Annex VI.

The regulation also allows for on-off controls for NO_X for auxiliary engines used on vessels powered by Category 3 engines. More broadly, § 1402.650(d) allows those auxiliary engines to be certified to MARPOL Annex VI standards instead of being certified to EPA's emission standards under 40 CFR part 1042. The regulation as originally written describes how these engines must comply with EPA's Tier 3 and Tier 4 standards in the same way that Category 3 engines must comply with EPA's Tier 2 and Tier 3 standards. However, since auxiliary engines installed on Category 3 vessels are certified to MARPOL Annex VI standards instead of EPA's emission standards, the regulation should describe how these auxiliary engines must meet the IMO Tier II and IMO Tier III NO_X standards to comply with the on-off control provisions under § 1042.115(g). These requirements related to the Engine International Air Pollution Prevention (EIAPP) certificates for engines with on-off controls are addressed under MARPOL Annex VI and 40 CFR part 1043.

3. Miscellaneous Marine Diesel Amendments

EPA is making several additional changes across 40 CFR part 1042 to correct errors, to add clarification, and to make adjustments based on lessons learned from implementing these regulatory provisions. Specifically, the final rule includes the following amendments:

Section 1042.101: Revise the instruction for specifying a longer useful life. The regulation as originally adopted states that engine design, advertising, and marketing may equally serve as the basis for establishing a longer useful life. We would not expect manufacturers to specify a longer useful life based only on advertising and marketing claims. The amendment emphasizes that design life is the basis for specifying a longer useful life, with the further explanation that the recommended overhaul interval can be understood, together with advertising and marketing materials and other relevant factors, to properly represent an engine's design life.

Section 1042.101: The Federal Register mistakenly published references to Tier 3 p.m. standards and Tier 4 p.m. standards. Since we intended for those standards to apply at all times, we are amending the regulation to properly refer to those as Tier 3 p.m. standards and Tier 4 p.m. standards.

Section 1042.115: Revise the provision related to on-off controls to clarify that we have designated NO_X Emission Control Areas (ECAs) for U.S. waters. We no longer need to reference a possible future ECA. We will rely on the U.S. ECA boundaries to establish the area in which engines with on-off controls for aftertreatment-based standards need to be fully operational.

Section 1042.125: Add maintenance requirements for fuel-water separator cartridges or elements as an additional example of maintenance that is not emission-related. This aligns with the maintenance specifications for land-based nonroad diesel engines in 40 CFR part 1039.

Section 1042.135: Revise the labeling instruction for engines installed in domestic-only vessels to clarify that it applies only for engines above 130 kW, and that it applies equally for commercial and recreational vessels. These changes both align the EPA regulations to more closely align with the international standards under MARPOL Annex VI.

Section 1042.145: Remove obsolete paragraphs. We proposed to revise § 1042.145(j) to adjust the provision related to using certified land-based engines in marine vessels; however, we are reconsidering those changes and may again pursue such further amendments to those provisions.

Section 1042.255: Clarify that doing anything to make information false or incomplete after submitting an application for certification is the same as submitting false or incomplete information. For example, if there is a change to any corporate information or engine parameters described in the manufacturer's previously submitted application for certification, the manufacturer must amend the application to include the new information. Amendments include additional minor changes to align regulatory text across programs.

Section 1042.302: For emission testing during sea trials for Category 3 engines with on-off controls, allow manufacturers the flexibility to omit testing in Tier 2 mode if they do not need aftertreatment to meet the Tier 2 standards. We are most interested in compliance with the Tier 3 standards, since those controls are active anytime vessels are operating within ECA boundaries. System design and calibration with aftertreatment involves greater uncertainty than engines that comply using only in-cylinder controls. As a result, we believe the compliance demonstration for Tier 2 mode adds value only if it involves aftertreatment.

Section 1042.650: Revise the introductory text to clarify that paragraphs (a) through (c) continue to apply only for Category 1 and Category 2 engines, and that the provisions related to auxiliary engines on Category 3 vessels in paragraph (d) apply equally for Category 3 auxiliary engines. By adding paragraph (d) with limitation described in the section's introductory text, we inadvertently excluded Category 3 auxiliary engines.

Section 1042.655: Clarify that measuring engine-out emissions for engines that use exhaust aftertreatment must account for the backpressure and other effects associated with the aftertreatment devices. While improving the alignment between measured results and modeled results, this change also has the effect of removing the expectation that engine-out (pre-catalyst) emissions must meet Tier 2 standards; this is intended to address the case in which an engine may meet the Tier 2 standards with a different SCR dosing strategy rather than by completely disabling the SCR system.

Section 1042.701: Remove the reference to emission credits from part 94. This reference is not needed since the records related to credit accounting do not identify credits as being from part 94 or 1042.

Section 1042.801: Remove the requirement to register fuels used to certify remanufacturing systems. EPA does not register fuels such as natural gas or liquefied petroleum gas, so it is not appropriate to impose such a registration requirement. The requirement continues to apply for remanufacturing systems that are based on diesel fuel additives.

Section 1042.901: Revise the definition of “low-hour” to state that engines with NO_X aftertreatment should qualify as “low-hour” up to 300 hours, with other engines qualifying as “low-hour” up to only 125 hours. This change shortens the low-hour testing period for recreational engines above 560 kW, and for commercial engines with maximum engine power between 560 and 600 kW. This change is intended to ensure that low-hour engine testing are properly represented as new engines that have not started to experience deterioration of emission controls. Engines with NO_X aftertreatment need extra time to achieve stabilized emission rates. In contrast, engines without NO_X aftertreatment reach a point of stabilized emission levels much sooner, which supports the shorter duration for low-hour testing before starting service accumulation. This does not preclude continued testing beyond 125 hours for engines without NO_X aftertreatment, but it would prevent manufacturers from planning test programs that extend well beyond 125 hours. We requested comment on this approach in the proposed rule, and EMA submitted comments supporting this adjustment.

Section 1043.41: Clarify that engine manufacturers may continue to produce new engines under an established EIAPP certificate after a change in emission standards for purposes other than installation in a new vessel. For example, manufacturers may need to produce engines certified to IMO Tier II NO_X standards after 2016 for installation as replacement engines in vessels built before 2016.

Sections 1042.910 and 1043.100: Incorporate by reference the 2017 edition of MARPOL Annex VI and the NO_X Technical Code, dated 2017, which contains all amendments through 2016.

H. Portable Fuel Containers (40 CFR Part 59)

EPA's emission standards and certification requirements for portable fuel containers are described in 40 CFR part 59. Section III.A describes an amendment related to test fuel specifications. In addition, we are adopting the following amendments:

Section 59.626: Correct the reference to additional testing to recognize that the manufacturer may need to test multiple containers.

Section 59.628: Align recordkeeping specifications with the provisions that apply for nonroad engines and equipment. This removes the ambiguity from applying specifications differently for different types of testing information. As noted in Section III.J, now that test records are stored electronically, there is no reason to differentiate testing information into routine and non-routine records.

Section 59.650: Revise the blending instruction to specify a lower level of precision; specifying a range of 10.0 ± 1.0 percent, which is consistent with the approach we take in 40 CFR 1060.515 and 1060.520.

Section 59.653: Correct the pressure specification for durability testing. The amendment adjusts the kPa value to match the psi value in the regulation. This aligns with the pressure testing specified for nonroad fuel tanks.

Section 59.653: Clarify that the fuel fill level needs to stay at 40 percent full throughout slosh testing. The container should be closed for the duration of the test, so this clarification is mainly intended to ensure that the fuel tank does not leak during the test.

Section 59.660: Revise the test exemption to clarify that anyone subject to regulatory prohibitions may ask for a testing exemption.

Section 59.664: Correct the web address for U.S. Department of Treasury Circular 570.

Section 59.680: Clarify how the definition of “portable fuel container” applies for different colors. The regulatory text states that red, yellow, and blue utility jugs qualify as portable fuel containers regardless of any contrary labeling or marketing. This is intended to prevent circumvention of emission standards with containers that would be commonly recognized as portable fuel containers. Containers that are not red, yellow, or blue qualify as fuel containers if they meet the criteria described in the definition. The amendment to clarify this point does not represent a change in policy. For example, anyone who sold uncertified purple portable fuel containers that were subject to standards may be in violation of the prohibitions in 40 CFR 59.602.

We received no adverse comments on the proposed amendments to 40 CFR part 59 and are adopting these amendments without modification.

I. Evaporative Emission Standards for Nonroad Spark-Ignition Engines and Equipment (40 CFR Part 1060)

EPA adopted evaporative emission standards and test procedures in 40 CFR part 1060. Section III.A describes amendments related to test fuel specifications. EPA is also adopting numerous changes across 40 CFR part 1060 to correct errors, to add clarification, and to make adjustments based on lessons learned from implementing these regulatory provisions. This includes the following changes:

Sections 1060.1 and 1060.801: Clarify how standards apply for portable nonroad fuel tanks.

Sections 1060.30 and 1060.825: Consolidate information-collection provisions into a single section.

Section 1060.104: Clarify that any approval from California ARB is sufficient for demonstrating compliance with running loss standards, rather than limiting this to approved Executive orders.

Section 1060.105: Clarify the requirement for tanks to be sealed to recognize the exception allowed under the regulation.

Sections 1060.105 and 1060.240: Allow manufacturers more generally to exercise the alternative of using procedures adopted by California ARB. This is necessary to allow testing with the E10 test fuel adopted by California ARB after the 2004 version of its regulation that is currently referenced in the Code of Federal Regulations.

Section 1060.120: Update the terminology to refer to “the date the equipment is sold to the ultimate purchaser” instead of the “point of first retail sale.” We also don't want to prohibit manufacturers from including components in the warranty if they fail without increasing evaporative emissions. These changes align with similar amendments in our other programs.

Section 1060.130: Clarify how manufacturers must identify limitations on the types of equipment covered by the application for certification, especially for fuel caps. We allow equipment manufacturers to certify their equipment using widely varying approaches for fuel caps. The equipment manufacturer's certification and testing method needs to be reflected in their instructions for anyone completing assembly of equipment from that equipment manufacturer.

Section 1060.135: Clarify how the equipment labeling provisions apply for engine manufacturers, and clarify that manufacturers need to apply labels at the time of manufacture. In many cases, the labeling is integral to the production process, such as for molded fuel tanks.

Section 1060.135: Allow for permanently identifying the date of manufacture somewhere other than the emission control information label using any method (not only stamping or engraving) and require that the manufacturer describe in the application for certification where the equipment identifies the date of manufacture.

Section 1060.135: We proposed to revise paragraph (b)(5) to simplify the equipment labeling options; however, we decided to defer action on this change in this rulemaking. This leaves the regulatory text unchanged, which allows all the existing labeling options available for manufacturers. We may consider amending these labeling provisions in a future rulemaking.

Section 1060.137: Clarify when and how to label fuel caps. This depends only on whether the fuel cap is certified, not on whether the fuel cap is mounted directly on the fuel tank. It is also important to include the part number on the fuel cap if the equipment is designed with a pressurized fuel tank.

Section 1060.205: Clarify that the application for certification needs to identify the EPA-issued emission family name if the certified configuration relies on one or more certified components.

Section 1060.205: Replace the requirement to submit data from invalid tests with a requirement to simply notify EPA in the application for certification if a test was invalidated.

Section 1060.225: Clarify how manufacturers may amend the application for certification during and after the model year, consistent with the current policy regarding field fixes.

Section 1060.235: Clarify that we can direct manufacturers to send test products to EPA for confirmatory testing, or to a different lab that we specify.

Section 1060.235: Add an explicit allowance for carryover engine families to include the same kind of within-family running changes that are currently allowed over the course of a model year. The original text may have been understood to require that such running changes be made separate from certifying the engine family for the new model year.

Section 1060.250: Remove references to routine and standard tests and remove the shorter recordkeeping requirement for routine data (or data from routine tests). We are adopting an amendment to require that all test records must be kept for eight years. With electronic recording of test data, there should be no advantage to keeping the shorter recordkeeping requirement for a subset of test data. EPA also notes that the eight-year period restarts with certification for a new model year if the manufacturer uses carryover data.

Section 1060.255: Clarify that doing anything to make information false or incomplete after submitting an application for certification is the same as submitting false or incomplete information. For example, if there is a change to any corporate information or parameters described in the manufacturer's previously submitted application for certification, the manufacturer must amend the application to include the new information. Amendments include additional minor changes to align regulatory text across programs.

Section 1060.505: Revise the provision describing alternative test procedures to align with parallel text in 40 CFR 1065.10(c). It is important to note that approved alternative procedures increase flexibility for certifying manufacturers without limiting available methods for EPA testing.

Section 1060.520: For slosh testing and for the preconditioning fuel soak, specify that the fuel fill level should not decrease during testing, other than what would occur from permeation and from any appropriate testing steps to perform durability tests during the preconditioning fuel soak. We also specify that leaking fuel tanks are never suitable for testing, even if there is a potential to repair the leak.

Section 1060.601: Remove the reference to fuel caps since there is no need for a separate description about how the regulatory prohibitions apply for fuel caps. As noted in § 1061.1(c), fuel cap manufacturers that choose to certify their fuel caps under 40 CFR part 1060 become subject to all the requirements associated with certification.

Section 1060.610: Adopt provisions clarifying how manufacturers can ship products that are not yet certified if that is needed for completing assembly at multiple locations, including shipment between companies and shipment between two facilities from a single company. These provisions are analogous to the provisions that apply for engines in 40 CFR 1068.260.

Section 1060.640: Migrate engine branding to 40 CFR 1068.45.

Section 1060.801: Update the contact information for the Designated Compliance Officer.

Section 1060.801: Revise the definition of “model year” to clarify that the calendar year relates to the time that engines are produced under a certificate of conformity.

Section 1060.801: Revise the definition of “placed into service” to prevent circumvention that may result from a manufacturer or dealer using a piece of equipment in a way that could otherwise cause it to no longer be new and subject to the prohibitions of 40 CFR 1068.101.

Section 1060.81: Correct the web address for the American Boat and Yacht Council.

Section 1060.815: Migrate provisions related to confidential business information to 40 CFR part 1068.

J. Additional Amendments for Nonroad Spark-Ignition Engines at or Below 19 kW (40 CFR Part 1054)

EPA's emission standards and certification requirements for nonroad spark-ignition engines at or below 19 kW are described in 40 CFR part 1054. EPA is adopting numerous changes across 40 CFR part 1054 to correct errors, to add clarification, and to make adjustments based on lessons learned from implementing these regulatory provisions. This includes the following changes:

Section 1054.1: Clarify that the provision allowing for voluntary certification under 40 CFR part 1054 for larger engines applies only for engines up to 30 kW and up to 1,000 cubic centimeters.

Section 1054.2: Add a clarifying note to say that a person or other entity other than a conventional “manufacturer” may need to certify engines that become new after being placed into service (such as engines converted from highway or stationary use). This is intended to address an assumption that only conventional manufacturers can certify engines.

Sections 1054.30, 1054.730, and 1054.825: Consolidate information-collection provisions into a single section.

Section 1054.120: Clarify that extended-warranty requirements apply for the emission-related warranty only to the extent that warranties are actually provided to the consumer, rather than to any published warranties that are offered. The principles are that the emission-related warranty should not be less effective for emission-related items than for items that are not emission-related, and that the emission-related warranty for a given component should not be less effective than the basic mechanical warranty for that same component.

Section 1054.125: Allow for special maintenance procedures that address low-use engines. For example, operators in certain circumstances may perform engine maintenance after a smaller number of hours than would otherwise apply.

Section 1054.130: Remove references to “nonroad” equipment to accommodate regulations for stationary engines in 40 CFR part 60, subpart JJJJ, that rely on these same provisions.

Section 1054.135: Allow for including optional label content only if this does not cause the manufacturer to omit other information based on limited availability of space on the label.

Section 1054.145: Remove obsolete content. Most of the provisions in this section were needed only for the transition to the Phase 3 standards. We are also clarifying that the provision that allows for testing with California Phase 2 test fuel applies only through model year 2019. California ARB requires testing with its Phase 3 test fuel starting in model year 2020.

Section 1054.205: Replace the requirement to submit data from invalid tests with a requirement to simply notify EPA in the application for certification if a test was invalidated.

Section 1054.205: Specify that the application for certification needs to include estimated initial and final dates for producing engines for the model year, and an estimated date for the initial introduction into U.S. commerce. This information helps with managing information in the application and overseeing testing and other compliance requirements. This amendment aligns with current practice.

• Section 1054.225: Simplify the instruction on changing the Family Emission Limit during the model year to specify that the manufacturer must identify the date of the change based only on the month and year. This change aligns with current practice for amending applications for certification.
• Section 1054.225: Clarify how manufacturers may amend the application for certification during and after the model year, consistent with the current policy regarding field fixes.
• Section 1054.235: Clarify that air-fuel ratio and other adjustable parameters are part of the selection of a worst-case test configuration for emission-data engines. If an engine has rich and lean settings, the manufacturer should determine which is the worst-case setting for emission measurements to determine deterioration factors. In particular, it is not appropriate to combine results from different settings to calculate any kind of average or composite value. Service accumulation between emission measurements may include any representative combination of those settings.
• Section 1054.235: Add an explicit allowance for carryover engine families to include the same kind of within-family running changes that are currently allowed over the course of a model year. The original text may have been understood to require that such running changes be made separate from certifying the engine family for the new model year.
• Section 1054.235: Clarify how EPA will calibrate engines within normal production tolerances for things that are not adjustable parameters.
• Sections 1054.235, 1054.240, 1054.245, 1054.601, and 1054.801: Describe how to demonstrate compliance with dual-fuel and flexible-fuel engines. This generally involves testing with each separate fuel, or with a worst-case fuel blend.
• Section 1054.240: Clarify that each measurement from emission-data vehicles must meet emission standards.
• Section 1054.245: Clarify the basis for EPA approval for using deterioration factors from other engines. EPA approval depends on the manufacturer demonstrating that emission measurements reasonably represent in-use deterioration for the engine family being certified. This copies in regulatory text that already applies under other EPA programs.
• Section 1054.245: Copy in the values and formulas used for assigned deterioration factors for handheld and nonhandheld engines. This includes a minor correction to the equation from 40 CFR 90.104(g) and a new description about combining deterioration factors for HC and NO_X, but otherwise maintains the current policy and practice for these deterioration factors.
• Section 1054.250: Remove references to routine and standard tests and remove the shorter recordkeeping requirement for routine data (or data from routine tests). We are adopting a requirement to keep all test records for eight years. With electronic recording of test data, there should be no advantage to keeping the shorter recordkeeping requirement for a subset of test data. EPA also notes that the eight-year period restarts with certification for a new model year if the manufacturer uses carryover data.
• Section 1054.255: Clarify that doing anything to make information false or incomplete after submitting an application for certification is the same as submitting false or incomplete information. For example, if there is a change to any corporate information or engine parameters described in the manufacturer's previously submitted application for certification, the manufacturer must amend the application to include the new information.
• Section 1054.255: Clarify that voiding certificates for a failure to comply with recordkeeping or reporting requirements will be limited to the certificates that relate to the particular recordkeeping or reporting failure.
• Section 1054.301: Clarify the process for requesting a small-volume exemption from production-line testing. This is better handled as preliminary approval under § 1054.210 rather than including it as part of the application for certification.
• Section 1054.310: Provide an example to illustrate how manufacturers may need to divide the annual production period into four quarters if it is longer (or shorter) than 52 weeks.
• Section 1054.315: Clarify that results from repeat tests can be averaged together, provided that the engine is not modified during the test program. This applies for engine modifications to switch to a different engine configuration or to improve emission control for a given engine configuration.
• Sections 1054.315 and 1054.320: Clarify how to manage test results for engines that fail an emission standard. Manufacturers must use the production line testing (PLT) test result from a failing engine regardless of the disposition of the failing engine. Manufacturers report test results after modifying a failing engine to show that it can be covered by the certificate of conformity, but manufacturers may factor these test results into PLT calculations only if the manufacturer changes production processes for all further engines to match the adjustments made to the failing engine. In that case, the test results from the modified engine count as a new test engine for the PLT calculations, rather than replacing the results from the engine before modifications. These regulatory changes codify the practice we have already established by guidance.

• Section 1054.505: Clarify the instructions for controlling torque at non-idle test modes, and for demonstrating compliance with cycle-validation criteria. The revised language more carefully describes the current practice for testing engines.
• Section 1054.620: Clarify that provisions apply for any kind of competition, not just racing.
• Sections 1054.625 and 1054.626: Remove obsolete text.
• Section 1054.640: Migrate engine branding provisions to § 1068.45.
• Section 1054.690: Correct the web address for U.S. Department of Treasury Circular 570 and clarify how an automatic suspension of a certificate of conformity applies for certain numbers of engines, and how U.S. Customs incorporates the bonding requirements into its entry procedures.
• Section 1054.701: Change terminology for counting engines from “intended for sale in the United States” to “U.S.-direction production volume.” This conforms to the usual approach for calculating emission credits for nonroad engines.
• Section 1054.710: Clarify that it is not permissible to show a proper balance of credits for a given model by using emission credits from a future model year.
• Section 1054.730: Clarify terminology for ABT reports.
• Section 1054.740: Remove obsolete content.
• Section 1054.801: Update the contact information for the Designated Compliance Officer.
• Section 1054.801: Remove the note from the definition of “handheld” describing which standards apply for various types of equipment. The note does not cover all the provisions that apply, which has led to more confusion than clarity.
• Section 1054.801: Revise the definition of “model year” to clarify that the calendar year relates to the time that engines are produced under a certificate of conformity.
• Section 1054.801: Revise the definition of “new nonroad engine” to clarify that imported engines become new based on the original date of manufacture, rather than the original model year. This clarification is necessary because 40 CFR 1068.360 requires redesignation of an imported engine's model year in certain circumstances.
• Section 1054.801: Revise the definition of “placed into service” to prevent circumvention that may result from a manufacturer or dealer using a piece of equipment in a way that could otherwise cause it to no longer be new and subject to the prohibitions of 40 CFR 1068.101.
• Section 1054.801: Revise the definition of “small-volume equipment manufacturer” to state that the volume limits apply for all calendar years, not just 2007 through 2009. We no longer use this definition for limiting the scope of transition or phase-in provisions. The provisions for reduced production-line testing, assigned deterioration factors, and reduced bonding burdens should apply without regard to the specific years identified in the original regulation adopting the Phase 3 standards.
• Section 1054.815: Migrate provisions related to confidential business information to 40 CFR Part 1068.

K. Amendments for General Compliance Provisions (40 CFR Part 1068)

We are amending the replacement engine exemption in § 1068.240 to adjust the criteria by which manufacturers qualify exempted engines under the tracked option in § 1068.240(b). Engine manufacturers may produce any number of exempt replacement engines if they meet all the specified requirements and conditions. To account for the timing of making the necessary demonstrations, the regulation specifies that engines must be designated as either tracked or untracked by September 30 following each production year, which coincides with the reporting requirement to document the number of exempt replacement engines each manufacturer produces. The regulation as adopted specifies that manufacturers must meet “all the requirements and conditions that apply under paragraph (b). . . .”

We proposed to amend the regulation to clarify that the requirement for the engine manufacturer to retrieve the replaced engine (or confirm that it had been destroyed) was not subject to the reporting deadline of September 30 following the production year. The Truck and EMA commented to suggest that it would be better to apply a later deadline rather than removing the deadline entirely. The specific suggestion was to require converting a replacement engine from tracked to untracked if the replaced engine was not recovered within five years. We agree that the suggested approach would be beneficial for ensuring that replaced engines are accounted for and believe that the reported information would fit within the scope of current compliance responsibilities for both manufacturers and EPA. We are therefore including this adjustment in the final rule.

We also requested comment on several possible adjustments to the replacement engine exemption to address manufacturers' concerns about complying with the limit of producing only 0.5 percent of their production volume for specified sizes and types of engines under the untracked option. This is most challenging for large engines with very low production volumes. California ARB commented to recommend keeping the 0.5 percent limit because it should be rare to need more exempt replacement engines, and the regulation already allows for a greater number of exempt replacement engines where manufacturers are able to meet the tracking requirements.

EMA commented with a suggestion that the manufacturers should be allowed to produce up to five exempt replacement engines under the untracked option, in addition to the 0.5 percent. This was intended to account for the fact that 0.5 percent of a couple hundred engines does not allow for any substantial flexibility to supply distributors with these exempt replacement engines. We recognize the limit of the percentage-based approach and agree that allowing five engines per year to meet demand for these engines is appropriate. We are leaving the 0.5 percent limit in place in this rulemaking, but we are including an adjustment to address the engine manufacturers' concerns about low-volume production. Rather than adding an allowance for these five engines for all companies and all sectors/categories, we are amending the regulation to allow for the greater of five engines or 0.5 percent of production. This focuses the amendment on the companies and product line where the percentage-based approach provides no substantial ability to participate in the untracked option for replacement engines. Allowing five engines makes a difference for engine models with annual production volumes below 900 for a given type and displacement category.

EMA had additional comments related to the limits and oversight provisions for the untracked option of the replacement engine exemption. As noted in the Response to Comments, we are deferring action on those broader comments until a future rulemaking.

L. Other Requests for Comment

The proposed rule described several areas where we were interested in comments to gather information, perspectives, and feedback on possible future rulemaking amendments. These comments are included in Chapter 4 of the Response to Comments. The other chapters of the Response to Comments also include several issues with similar input regarding potential future rulemaking amendments.

IV. Statutory Authority and Executive Order Reviews

Additional information about these statutes and Executive orders can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

This action is not a significant regulatory action and was therefore not submitted to the Office of Management and Budget (OMB) for review.

B. Paperwork Reduction Act (PRA)

This action does not impose any new information collection burden under the PRA. OMB has previously approved the information collection activities contained in the existing regulations and has assigned OMB control numbers 2060-0104, 2060-0287, 2060-0338, 2060-0545, 2060-0641. This rule clarifies and simplifies procedures without affecting information collection requirements.

C. Regulatory Flexibility Act (RFA)

I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. In making this determination, the impact of concern is any significant adverse economic impact on small entities. An agency may certify that a rule will not have a significant economic impact on a substantial number of small entities if the rule relieves regulatory burden, has no net burden or otherwise has a positive economic effect on the small entities subject to the rule. This action is designed to reduce testing burdens, increase compliance flexibility, and make various corrections and adjustments to compliance provisions; as a result, we anticipate no costs associated with this rule. We have therefore concluded that this action will have no net regulatory burden for directly regulated small entities.

D. Unfunded Mandates Reform Act (UMRA)

This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. This action imposes no enforceable duty on any state, local or tribal governments. Requirements for the private sector do not exceed $100 million in any one year.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the National Government and the states, or on the distribution of power and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

This action does not have tribal implications as specified in Executive Order 13175. This rule will be implemented at the Federal level and affects engine and vehicle manufacturers. Thus, Executive Order 13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

This action is not subject to Executive Order 13045 because it is not economically significant as defined in Executive Order 12866, and because the EPA does not believe the environmental health or safety risks addressed by this action present a disproportionate risk to children.

H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution or Use

This action is not subject to Executive Order 13211, because it is not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR Part 51

Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (“NTTAA”), Public Law 104-113, 12(d) (15 U.S.C. 272 note) directs EPA to use voluntary consensus standards in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards are technical standards (e.g., materials specifications, test methods, sampling procedures, and business practices) that are developed or adopted by voluntary consensus standards bodies. NTTAA directs agencies to provide Congress, through OMB, explanations when the Agency decides not to use available and applicable voluntary consensus standards. This action involves technical standards.

Except for the standards discussed below, the standards included in the regulatory text as incorporated by reference (in parts 60, 86, 1036, 1037, 1060, and 1065) were all previously approved for IBR and no change is included in this action.

In accordance with the requirements of 1 CFR 51.5, we are incorporating by reference the use of test methods and standards from ASTM International. This includes the following standards and test methods:

The referenced standards and test methods may be obtained through the ASTM International website (www.astm.org) or by calling ASTM at (610) 832-9585.

As described in Section II.A.5, EPA is publishing a new version of the Greenhouse Gas emissions Model (GEM), which manufacturers will use for certifying heavy-duty highway vehicles to the Phase 2 GHG emission standards in 40 CFR part 1037. The model calculates GHG emission rates for heavy-duty highway vehicles based on input values defined by the manufacturer. GEM Version 3.5.1 applies for all Phase 2 vehicles. GEM also includes a Hardware-in-Loop submodel to simulate vehicle engines, transmissions, and other powertrain components. These models are referenced in §§ 1037.520, 1037.550, and 1037.801. The models are available as noted in the amended regulations at 40 CFR 1037.810.

We are removing numerous referenced documents as part of the effort to remove obsolete provisions in 40 CFR parts 85 through 94 and elsewhere.

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

The EPA believes this action does not have disproportionately high and adverse human health or environmental effects on minority populations, low-income populations or indigenous peoples, as specified in Executive Order 12898 (59 FR 7629, February 16, 1994). Due to the small environmental impact, this regulatory action will not have a disproportionate adverse effect on minority populations, low-income populations, or indigenous peoples.

K. Congressional Review Act (CRA)

This action is subject to the CRA, and EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This action is not a “major rule” as defined by 5 U.S.C. 804(2).

L. Judicial Review

Under CAA section 307(b)(1), judicial review of this final rule is available only by filing a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit by August 30, 2021. Under CAA section 307(d)(7)(B), only an objection to this final rule that was raised with reasonable specificity during the period for public comment can be raised during judicial review. Section 307(d)(7)(B) of the Clean Air Act also provides a mechanism for EPA to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” Any person seeking to make such a demonstration should submit a Petition for Reconsideration to the Office of the Administrator, Environmental Protection Agency, Room 3000, William Jefferson Clinton Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, with an electronic copy to the person listed in FOR FURTHER INFORMATION CONTACT, and the Associate General Counsel for the Air and Radiation Law Office, Office of General Counsel (Mail Code 2344A), Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20004. Note that under CAA section 307(b)(2), the requirements established by this final rule may not be challenged separately in any civil or criminal proceedings brought by EPA to enforce these requirements.

List of Subjects

40 CFR Part 9

• Reporting and recordkeeping requirements

40 CFR Part 59

• Air pollution control
• Confidential business information
• Labeling
• Ozone
• Reporting and recordkeeping requirements
• Volatile organic compounds

40 CFR Part 60

• Administrative practice and procedure
• Air pollution control
• Aluminum
• Beverages
• Carbon monoxide
• Chemicals
• Coal
• Electric power plants
• Fluoride
• Gasoline
• Glass and glass products
• Grains
• Greenhouse gases
• Household appliances
• Incorporation by reference
• Industrial facilities
• Insulation
• Intergovernmental relations
• Iron
• Labeling
• Lead
• Lime
• Metals
• Motor vehicles
• Natural gas
• Nitrogen dioxide
• Petroleum
• Phosphate
• Plastics materials and synthetics
• Polymers
• Reporting and recordkeeping requirements
• Rubber and rubber products
• Sewage disposal
• Steel
• Sulfur oxides
• Vinyl
• Volatile organic compounds
• Waste treatment and disposal
• Zinc

40 CFR Part 85

• Confidential business information
• Greenhouse gases
• Imports
• Labeling
• Motor vehicle pollution
• Reporting and recordkeeping requirements
• Research
• Warranties

40 CFR Part 86

• Administrative practice and procedure
• Confidential business information
• Incorporation by reference
• Labeling
• Motor vehicle pollution,

40 CFR Part 88

• Labeling
• Motor vehicle pollution
• Reporting and recordkeeping requirements

40 CFR Part 89

• Administrative practice and procedure
• Confidential business information
• Imports
• Labeling
• Motor vehicle pollution
• Reporting and recordkeeping requirements
• Research
• Vessels
• Warranties

40 CFR Part 90

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Reporting and recordkeeping requirements
• Research
• Warranties

40 CFR Part 91

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 92

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Railroads
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 94

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Penalties
• Reporting and recordkeeping requirements
• Vessels
• Warranties

40 CFR Part 1027

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Reporting and recordkeeping requirements

40 CFR Part 1033

• Administrative practice and procedure
• Confidential business information
• Environmental protection
• Labeling
• Penalties
• Railroads
• Reporting and recordkeeping requirements

40 CFR Part 1036

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Environmental protection
• Greenhouse gases
• Incorporation by reference
• Labeling
• Motor vehicle pollution
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1037

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Environmental protection
• Incorporation by reference
• Labeling
• Motor vehicle pollution
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1039

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1042

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Environmental protection
• Imports
• Incorporation by reference
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Vessels
• Warranties

40 CFR Part 1043

• Administrative practice and procedure
• Air pollution control
• Imports
• Incorporation by reference
• Reporting and recordkeeping requirements
• Vessels

40 CFR Part 1045

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1048

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Research
• Warranties

40 CFR Part 1051

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1054

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1060

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Incorporation by reference
• Labeling
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1065

• Administrative practice and procedure
• Air pollution control
• Incorporation by reference
• Reporting and recordkeeping requirements
• Research

40 CFR Part 1066

• Air pollution control
• Incorporation by reference
• Reporting and recordkeeping requirements

40 CFR Part 1068

• Administrative practice and procedure
• Air pollution control
• Confidential business information
• Imports
• Motor vehicle pollution
• Penalties
• Reporting and recordkeeping requirements
• Warranties

40 CFR Part 1074

• Administrative practice and procedure
• Air pollution control

For the reasons set out in the preamble, we are amending title 40, chapter I of the Code of Federal Regulations as set forth below.

PART 9—OMB APPROVALS UNDER THE PAPERWORK REDUCTION ACT

1. The authority citation for part 9 continues to read as follows:

Authority: 7 U.S.C. 135 et seq., 136-136y; 15 U.S.C. 2001, 2003, 2005, 2006, 2601-2671; 21 U.S.C. 331j, 346a, 31 U.S.C. 9701; 33 U.S.C. 1251 et seq., 1311, 1313d, 1314, 1318, 1321, 1326, 1330, 1342, 1344, 1345(d) and (e), 1361; E.O. 11735, 38 FR 21243, 3 CFR, 1971-1975 Comp. p. 973; 42 U.S.C. 241, 242b, 243, 246, 300f, 300g, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-1, 300j-2, 300j-3, 300j-4, 300j-9, 1857 et seq., 6901-6992k, 7401-7671q, 7542, 9601-9657, 11023, 11048.

2. Amend § 9.1 by:

a. Removing entries for 85.1403 through 85.1415, 85.1514, 85.1712, 85.1808, 85.2208, and 85.2401-85.2409;

b. Revising the entries under the heading “Control of Emissions From New and In-Use Highway Vehicles and Engine”;

c. Removing the heading “Clean-Fuel Vehicles” and the items under that heading;

d. Removing the heading “Control of Emissions From New and In-Use Nonroad Compression-Ignition Engines” and the items under that heading;

e. Removing the heading “Control of Emissions From New and In-use Nonroad Engines” and the items under that heading;

f. Removing the heading “Control of Emissions From New and In-Use Marine Compression-Ignition Engines” and the items under that heading;

g. Revising the entries under the heading “Fuel Economy of Motor Vehicles”;

h. Removing the entry for “1033.825” and adding the entry “1033.925” in its place; and

i. Removing the entry for “1042.825” and adding the entry “1042.925” in its place.

The revisions and additions read as follows:

PART 59—NATIONAL VOLATILE ORGANIC COMPOUND EMISSION STANDARDS FOR CONSUMER AND COMMERCIAL PRODUCTS

3. The authority citation for part 59 continues to read as follows:

Authority: 42 U.S.C. 7414 and 7511b(e).

Subpart F—Control of Evaporative Emissions From New and In-Use Portable Fuel Containers

4. Amend § 59.626 by revising paragraph (e) to read as follows:

5. Amend § 59.628 by revising paragraph (b) to read as follows:

6. Amend § 59.650 by revising paragraph (c) to read as follows:

7. Amend § 59.653 by revising paragraphs (a)(1) and (3) and (a)(4)(ii)(C) to read as follows:

8. Amend § 59.660 by revising paragraph (b) to read as follows:

9. Amend § 59.664 by revising paragraph (c) to read as follows:

10. Amend § 59.680 by revising the definition of “Portable fuel container” to read as follows:

PART 60—STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

11. The authority citation for part 60 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq.

12. Amend § 60.4200 by revising paragraph (d) to read as follows:

13. Amend § 60.4201 by revising paragraphs (a), (d) introductory text, (f) introductory text, and (h) to read as follows:

14. Amend § 60.4202 by revising paragraphs (a)(1)(i), (a)(2), (b)(2), (e) introductory text, and (g) introductory text to read as follows:

15. Amend § 60.4204 by revising paragraphs (a) and (f) to read as follows:

16. Amend § 60.4205 by revising paragraph (a) to read as follows:

17. Amend § 60.4210 by revising paragraphs (a) and (b), (c) introductory text, (c)(3), (d), (i), and (j) and adding paragraph (k) to read as follows:

18. Amend § 60.4211 by revising paragraphs (a)(3) and (b)(1) to read as follows:

19. Amend § 60.4212 by revising paragraphs (a) and (c) and removing the undesignated paragraph following the equation in paragraph (c) to read as follows:

20. Amend § 60.4216 by revising paragraphs (b) and (c) to read as follows:

21. Amend § 60.4219 by revising the definition for “Certified emissions life” to read as follows:

22. Amend § 60.4230 by revising paragraph (e) to read as follows:

23. Amend § 60.4231 by revising paragraphs (a) through (d) to read as follows:

24. Revise § 60.4238 to read as follows:

25. Revise § 60.4239 to read as follows:

26. Revise § 60.4240 to read as follows:

27. Amend § 60.4241 by revising paragraphs (a), (b), and (i) to read as follows:

28. Revise § 60.4242 to read as follows:

29. Amend § 60.4243 by revising paragraph (f) to read as follows:

30. Amend § 60.4245 by revising paragraph (a)(3) to read as follows:

31. Amend § 60.4247 by revising paragraph (a) to read as follows:

32. Amend § 60.4248 by revising the definition for “Certified emissions life” and “Certified stationary internal combustion engine” to read as follows:

PART 85—CONTROL OF AIR POLLUTION FROM MOBILE SOURCES

33. The authority citation for part 85 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart O—[Removed and Reserved]

34. Remove and reserve subpart O, consisting of §§ 85.1401 through 85.1415.

35. Amend § 85.1501 by revising paragraph (a) to read as follows:

36. Amend § 85.1511 by adding introductory text and paragraph (b)(5) to read as follows:

37. Revise § 85.1514 to read as follows:

38. Amend § 85.1701 by revising paragraph (a)(1) to read as follows:

39. Revise § 85.1712 to read as follows:

40. Revise § 85.1801 to read as follows:

41. Revise § 85.1807 to read as follows:

42. Revise § 85.1808 to read as follows:

43. Amend § 85.1902 by revising paragraph (b)(2) to read as follows:

44. Amend § 85.2102 by revising paragraph (a)(18) and adding and reserving paragraph (b) to read as follows:

45. Amend § 85.2115 by revising paragraph (a)(4) to read as follows:

46. Revise § 85.2301 to read as follows:

PART 86—CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES

47. The authority citation for part 86 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

48. Section 86.1 is amended by:

a. Revising the last sentence of paragraph (a);

b. Redesignating paragraphs (b)(19) through (21) as paragraphs (b)(21) through (23); and

c. Adding new paragraphs (b)(19) and (20).

The revision and additions read as follows:

49. Section 86.004-15 is amended by revising paragraph (a)(1) to read as follows:

50. Section 86.010-18 is amended by—

a. Revising paragraphs (g)(2)(ii)(B) and (g)(2)(iii)(C).

b. Adding paragraph (g)(2)(iii)(D).

c. Removing and reserving paragraph (l)(2)(ii).

d. Revising paragraphs (p)(3) and (4).

The revisions and additions read as follows:

51. Section 86.113-04 is amended by revising paragraph (a)(1) to read as follows:

52. Section 86.129-00 is amended by revising paragraph (f)(1)(ii)(C) to read as follows:

53. Section 86.130-96 is amended by revising paragraph (a) to read as follows:

54. Section 86.213 is amended by revising paragraph (a)(2) to read as follows:

55. Remove § 86.401-97.

56. Amend § 86.408-78 by adding paragraphs (c) and (d) to read as follows:

57. Remove § 86.413-78.

58. Amend § 86.419-2006 by revising paragraph (b) introductory text to read as follows:

59. Amend § 86.427-78 by revising paragraph (a)(1) to read as follows:

60. Amend § 86.435-78 by revising paragraph (b)(1) to read as follows:

61. Amend § 86.436-78 by revising paragraph (d) to read as follows:

62. Amend § 86.513 by revising paragraph (a)(1) and adding paragraph (a)(3) to read as follows:

63. Revise § 86.531-78 to read as follows:

64. Revise § 86.1362 to read as follows:

Subpart P—[Removed and Reserved]

65. Remove and reserve subpart P.

Subpart Q—[Removed and Reserved]

66. Remove and reserve subpart Q.

67. Amend § 86.1803-01 by revising the definitions for “Heavy-duty vehicle” and “Light-duty truck” to read as follows:

68. Amend § 86.1811-17 by revising paragraph (b)(8)(iii)(C) to read as follows:

69. Amend § 86.1813-17 by revising the introductory text and paragraph (a)(2)(i) introductory text to read as follows:

70. Amend § 86.1817-05 by revising paragraph (a)(1) to read as follows:

71. Amend § 86.1818-12 by revising paragraph (d) to read as follows:

72. Amend § 86.1838-01 by revising paragraph (c)(2)(iii) to read as follows:

73. Amend § 86.1868-12 by revising paragraph (g) introductory text and adding paragraph (g)(5) to read as follows:

74. Part 88 is revised to read as follows:

PART 88—CLEAN-FUEL VEHICLES

Authority: 42 U.S.C. 7410, 7418, 7581, 7582, 7583, 7584, 7586, 7588, 7589, 7601(a).

75. Part 89 is revised to read as follows:

PART 89—CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES

Authority: 42 U.S.C. 7401-7671q.

76. Part 90 is revised to read as follows:

PART 90—CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS

Authority: 42 U.S.C. 7401-7671q.

77. Part 91 is revised to read as follows:

PART 91—CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES

Authority: 42 U.S.C. 7401-7671q.

78. Part 92 is revised to read as follows:

PART 92—CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES

Authority: 42 U.S.C. 7401-7671q.

79. Part 94 is revised to read as follows:

PART 94—CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES

Authority: 42 U.S.C. 7401-7671q.

PART 1027—FEES FOR VEHICLE AND ENGINE COMPLIANCE PROGRAMS

80. The authority citation for part 1027 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

81. The heading for part 1027 is revised to read as set forth above.

82. Amend § 1027.101 by:

a. Revising paragraph (a); and

b. Removing and reserving paragraph (b).

The revision reads as follows:

83. Revise § 1027.105 to read as follows:

84. Amend § 1027.110 by revising paragraph (a) introductory text to read as follows:

85. Amend § 1027.125 by revising paragraph (e) to read as follows:

86. Amend § 1027.130 by revising paragraphs (a) and (b) to read as follows:

87. Amend § 1027.135 by revising paragraph (b) to read as follows:

88. Revise § 1027.155 to read as follows:

PART 1033—CONTROL OF EMISSIONS FROM LOCOMOTIVES

89. The authority citation for part 1033 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

90. Amend § 1033.150 by:

a. Removing and reserving paragraphs (a) and (d).

b. Revising paragraph (e) introductory text.

c. Removing and reserving paragraphs (h) through (j).

d. Removing paragraphs (l) and (m).

The revision reads as follows:

91. Revise § 1033.255 to read as follows:

92. Amend § 1033.601 by revising paragraphs (c)(4) and (5) to read as follows:

93. Amend § 1033.701 by revising paragraph (k)(1) to read as follows:

94. Amend § 1033.740 by revising the introductory text and paragraph (a) to read as follows:

95. Amend § 1033.901 by revising paragraph (1) of the definition of “New” to read as follows:

96. Amend § 1033.925 by revising paragraph (e) introductory text to read as follows:

PART 1036—CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY HIGHWAY ENGINES

97. The authority citation for part 1036 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

98. Amend § 1036.1 by adding paragraph (b)(3) to read as follows:

99. Amend § 1036.108 by revising paragraph (a) to read as follows:

100. Amend § 1036.150 by revising paragraphs (e), (g), and (p)(2) and adding paragraph (q) to read as follows:

101. Amend § 1036.225 by revising paragraphs (e) and (f)(1) to read as follows:

102. Amend § 1036.230 by revising paragraph (d) and adding paragraph (f) to read as follows:

103. Amend § 1036.235 by revising the introductory text and paragraphs (b) and (c) to read as follows:

104. Revise § 1036.255 to read as follows:

105. Revise the heading for subpart D to read as follows:

Subpart D—Testing Production Engines and Hybrid Powertrains

106. Amend § 1036.301 by revising paragraph (b)(2) to read as follows:

107. Amend § 1036.501 by revising paragraph (g) and adding paragraph (h) to read as follows:

108. Add § 1036.503 to read as follows:

109. Revise § 1036.505 to read as follows:

110. Revise § 1036.510 to read as follows:

111. Amend § 1036.525 by revising paragraphs (a), (d) introductory text, and (d)(4) to read as follows:

112. Add § 1036.527 to read as follows:

113. Revise § 1036.530 to read as follows:

114. Revise § 1036.535 to read as follows:

115. Revise § 1036.540 to read as follows:

116. Add § 1036.543 to read as follows:

117. Amend § 1036.620 by revising paragraphs (a) and (b)(1)(iii) to read as follows:

118. Amend § 1036.701 by revising paragraphs (i) and (j) to read as follows:

119. Amend § 1036.705 by revising paragraphs (b)(2) and (5) to read as follows:

120. Amend § 1036.801 by:

a. Revising the definitions for “Auxiliary emission control device”, “Heavy-duty vehicle”, and “Hybrid”.

b. Adding definitions for “Hybrid engine”, “Hybrid powertrain”, and “Mild hybrid” in alphabetical order.

c. Revising the definition for “Steady-state”.

The revisions and additions read as follows:

121. Amend § 1036.805 by revising paragraphs (b) through (f) and adding paragraph (g) to read as follows:

122. Revise § 1036.810 to read as follows:

123. Amend § 1036.825 by revising paragraph (a) to read as follows:

Appendix I to Part 1036 [Redesignated as Appendix C to Part 1036]

124. Redesignate appendix I to part 1036 as appendix C to part 1036.

125. Add appendix A to part 1036 to read as follows:

Appendix A to Part 1036—Summary of Previous Emission Standards

The following standards, which EPA originally adopted under 40 CFR part 85 or 86, apply to compression-ignition engines produced before model year 2007 and to spark-ignition engines produced before model year 2008:

(a) Smoke. Smoke standards applied for compression-ignition engines based on opacity measurement using the test procedures in 40 CFR part 86, subpart I, as follows:

(1) Engines were subject to the following smoke standards for model years 1970 through 1973:

(i) 40 percent during the engine acceleration mode.

(ii) 20 percent during the engine lugging mode.

(2) The smoke standards in 40 CFR 86.11 started to apply in model year 1974.

(b) Idle CO. A standard of 0.5 percent of exhaust gas flow at curb idle applied through model year 2016 to the following engines:

(1) Spark-ignition engines with aftertreatment starting in model year 1987. This standard applied only for gasoline-fueled engines through model year 1997. Starting in model year 1998, the same standard applied for engines fueled by methanol, LPG, and natural gas. The idle CO standard no longer applied for engines certified to meet onboard diagnostic requirements starting in model year 2005.

(2) Methanol-fueled compression-ignition engines starting in model year 1990. This standard also applied for natural gas and LPG engines starting in model year 1997. The idle CO standard no longer applied for engines certified to meet onboard diagnostic requirements starting in model year 2007.

(c) Crankcase emissions. The requirement to design engines to prevent crankcase emissions applied starting with the following engines:

(1) Spark-ignition engines starting in model year 1968. This standard applied only for gasoline-fueled engines through model year 1989, and applied for spark-ignition engines using other fuels starting in model year 1990.

(2) Naturally aspirated diesel-fueled engines starting in model year 1985.

(3) Methanol-fueled compression-ignition engines starting in model year 1990.

(4) Naturally aspirated gaseous-fueled engines starting in model year 1997, and all other gaseous-fueled engines starting in 1998.

(d) Early steady-state standards. The following criteria standards applied to heavy-duty engines based on steady-state measurement procedures:

(e) Transient emission standards for spark-ignition engines. The following criteria standards applied for spark-ignition engines based on transient measurement using the test procedures in 40 CFR part 86, subpart N. Starting in model year 1991, manufacturers could generate or use emission credits for NO_X and NO_X + NMHC standards. Table 2 to this appendix follows:

(f) Transient emission standards for compression-ignition engines. The following criteria standards applied for compression-ignition engines based on transient measurement using the test procedures in 40 CFR part 86, subpart N. Starting in model year 1991, manufacturers could generate or use emission credits for NO_X, NO_X + NMHC, and PM standards. Table 3 to this appendix follows:

126. Add appendix B to part 1036 to read as follows:

Appendix B to Part 1036—Transient Duty Cycles

(a) This appendix specifies transient duty cycles for the engine and powertrain testing described in § 1036.510, as follows:

(1) The transient duty cycle for testing engines involves a schedule of normalized engine speed and torque values.

(2) The transient duty cycles for powertrain testing involves a schedule of vehicle speeds and road grade. Determine road grade at each point based on the peak rated power of the powertrain system, P_rated, determined in § 1036.527 and road grade coefficients using the following equation:

(b) The following transient duty cycle applies for spark-ignition engines and powertrains:

(c) The following transient duty cycle applies for compression ignition engines and powertrains:

PART 1037—CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES

127. The authority citation for part 1037 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

128. Amend § 1037.103 by revising paragraph (c) to read as follows:

129. Amend § 1037.105 by revising paragraph (h)(1) to read as follows:

130. Amend § 1037.106 by revising paragraphs (b) and (f)(2)(i) to read as follows:

131. Amend § 1037.115 by revising paragraph (e) to read as follows:

132. Amend § 1037.120 by revising paragraph (b)(1)(i) and (ii) to read as follows:

133. Amend § 1037.135 by removing and reserving paragraph (c)(4).

134. Amend § 1037.140 by revising paragraphs (g) and (h) to read as follows:

135. Amend § 1037.150 by revising paragraphs (c), (q)(2), (s), (u), (x) introductory text, (y), (z), and (aa) to read as follows:

136. Amend § 1037.201 by revising paragraph (h) to read as follows:

137. Amend § 1037.205 by revising paragraphs (e) and (f) to read as follows:

138. Amend § 1037.225 by revising paragraph (e) to read as follows:

139. Amend § 1037.230 by revising paragraph (a)(2) to read as follows:

140. Amend § 1037.231 by revising paragraph (b)(7) to read as follows:

141. Amend § 1037.235 by revising paragraphs (a), (c)(2), and (h) to read as follows:

142. Amend § 1037.243 by revising paragraph (c) to read as follows:

143. Revise § 1037.255 to read as follows:

144. Amend § 1037.301 by revising paragraph (b) to read as follows:

145. Amend § 1037.305 by revising the introductory text and paragraph (a) to read as follows:

146. Revise § 1037.320 to read as follows:

147. Amend § 1037.501 by adding paragraph (i) to read as follows:

148. Amend § 1037.510 by revising paragraphs (a)(2), (c)(3), (d), and (e) to read as follows: