Freightliner Corporation (Freightliner) of Portland, Oregon, has determined that some of its vehicles fail to meet the brake release time requirements of paragraph S5.3.4.1(b) of Federal Motor Vehicle Safety Standard (FMVSS) No. 121, Air Brake Systems. On May 8, 1997, Freightliner filed a noncompliance information report pursuant to 49 CFR Part 573.5. In that report, Freightliner indicated that it would file a petition for inconsequential noncompliance at a future date. Freightliner states that a Petition for Inconsequential Noncompliance dated October 10, 1997 was submitted to the agency but we have no record of it. Subsequently, on February 29, 2000, Freightliner resubmitted its Petition dated October 10, 1997.
This notice of receipt of the application is published under 49 U.S.C. 30118 and 30120, and does not represent an agency decision or other exercise of judgement concerning the merits of the application.
Under the requirements of S5.3.4.1(a) of FMVSS No. 121, each truck equipped with air brakes is required to have a pressure reduction from 95 psi to 5 psi, measured at each brake chamber of the truck, in not more than 0.55 second from the initial movement (release) of the service brake control. In addition, S5.3.4.1(b) requires that a truck which is equipped to tow another air-braked vehicle is required to have a pressure reduction from the initial test pressure equivalent to 95 psi in the truck's brake chambers, to 5 psi in not more than 0.75 second, measured in a 50-cubic-inch test reservoir attached to the control line coupling, upon initial movement (release) of the service brake control. Thus the pressure in the test reservoir is required to drop from approximately 95 psi to 5 psi in not more than 0.75 second upon release of the service brake control.
Number of Non-Complying Trucks
From January 1994 through April 1996, Freightliner produced approximately 3,145 Model FLD trucks that may not have had a quick-release valve installed at the control line coupling and therefore may not meet the release timing requirements in FMVSS No. 121. Data on the number of vehicles of the 3,145 affected truck population that were built without the quick release valve are as follows. According to Freightliner's noncompliance information report, a field inspection of 34 subject vehicles indicated that 5.9 percent (two trucks) did not have the quick release valves. According to Freightliner's petition for inconsequential noncompliance, an inspection (of an unspecified number) of trucks at the St. Thomas Manufacturing Plant where these vehicles were manufactured indicated that 69 percent were manufactured without the quick release valve. Freightliner also said in its petition that a field inspection of 38 subject trucks indicated that 9 percent did not have the quick release valve installed.
We telephoned Mr. Tony Moore of Freightliner's engineering department and Mr. Larry Winslow of Freightliner's compliance department on April 4, 2000, to clarify the numbers of non-compliant vehicles and two other subjects that are discussed below. The field inspection of 38 trucks indicated in the petition included the 34 trucks identified in the noncompliance information report. When asked about the number of vehicles inspected at the St. Thomas plant, Freightliner indicated that it has documentation showing that 303 trucks were inspected, and 70 trucks or 23 percent did not have quick release valves installed. Freightliner could not locate documentation regarding how the 69 percent number in the petition was derived and believes that this number is incorrect per the documentation it now has.
Brake Release Times of Non-Complying Trucks
FMVSS No. 121, paragraph S5.3.4.1(b), requires that the release timing measured in the test reservoir from initial pressure to 5 psi shall be 0.75 second. In its petition, Freightliner states that it conducted a test program to predict the actual release timing of the subject vehicles. The results are as indicated in the table below:
| [Predicted] release timing (seconds) | Vehicle population | Percent of population |
|---|---|---|
| 0.76-0.80 | 773 | 24.5 |
| 0.81-0.85 | 1759 | 55.9 |
| 0.86-0.90 | 602 | 19.1 |
| 0.91-0.95 | 1 | 0.03 |
| 0.96-1.00 | 10 | 0.3 |
| over 1.00 | 0 | 0 |
In the April 4, 2000 telephone conversation, Freightliner indicated that this prediction of release timing is based upon the length of the air tubing from the treadle valve to the trailer service air line glad hand coupling. The overall length of the air tubing varies with tractor wheelbase and the resulting vehicle population numbers in the table were derived on this basis. Without the quick release valve, the air is released through the treadle valve. As indicated in Freightliner's petition, the installation of the quick release valve releases the air at the tractor end of the trailer service air line.
Freightliner Rationale for Inconsequentiality to Safety
Freightliner does not believe that tractor glad hand timing between 0.75 and 1.00 second poses any risk or compromises highway safety. It states that brake application pressures at a highway speed of 55 mph rarely exceed 20 psi, and that when comparing the release timing from 20 psi on vehicles that would have 0.90 and 0.75 second release timing when tested according to FMVSS No. 121, the actual time differential drops to less than 0.10 second. In the April 4, 2000, telephone conversation, Freightliner clarified that the 0.10 second timing is the time for the pressure to be reduced at the glad hand coupling from 20 psi to 5 psi on trucks with no quick release valve installed. Freightliner also indicated that it did not do a comparable analysis of release timing from 20 psi with the quick release valve installed.
Freightliner believes that glad hand timing requirements were established primarily for the purpose of improving the application timing balance of combination vehicles, not the release timing. Freightliner cites the summary in Docket No. 85-07, Notice 3, as follows:
The purpose of the glad hand timing requirements is to ensure that the air delivery from towing vehicles to towed vehicles is fast enough to apply the brakes of all vehicles in the combination at approximately the same time, thereby avoiding a reduction in the combination stability (e.g., trailer bumping) caused by a slow glad hand.
Freightliner states that release timing is not mentioned, and that some commenters in the same docket questioned NHTSA's research in justifying the proposed release timing requirement. Freightliner indicates that one commenter stated that it is difficult to determine the effect of trailer release timing and tractor/trailer release differentials on compatibility and suggested testing indicated 0.90 second is sufficient. Freightliner also indicates that another commenter argued that a 1.00 second release timing would be more practical and accomplish the objective of the proposal, and that NHTSA stated that:
A short glad hand release time is not as important for safety and, in fact, it is not desirable to have the glad hand release before the tractor brakes.
Freightliner believes that requiring the rearmost vehicle to release last tends to “stretch” out the unit (vehicle combination) and make it more stable, and that slower than the required release time may actually help overall stability.
Freightliner summarizes its petition by stating that an estimated 280 to 2170 tractors were manufactured without quick release valves such that the glad hand release timing may be slightly higher than the 0.75 second specified in FMVSS No. 121, and that nearly all (99.6 percent) do not exceed 0.90 second. Freightliner believes that this timing difference of 0.0 to 0.15 second has no discernable or measurable effect on braking performance and thus no detrimental effect on highway safety. Therefore, it requests that we grant its petition to exempt it from the notification and remedy requirements of the Motor Vehicle Safety Act.
Comments and Docket Submissions
Interested persons are invited to submit written data, views, and arguments on Freightliner's petition for inconsequential noncompliance described above. Comments should refer to the Docket Number and be submitted to Docket Management at the address given above under ADDRESSES.
All comments received before the close of business on the closing date indicated below will be considered. The application, supporting materials, and comments also will be filed in the docket. Comments received after the closing date will also be filed and considered to the extent possible. When the petition is granted or denied, the notice will be published in the Federal Register pursuant to the authority indicated below.
Comment closing date: June 30, 2000.
(15 U.S.C. 1417; delegation of authority at 49 CFR 1.50 and 49 CFR 501.8)
Issued on: May 23, 2000.
Stephen R. Kratzke,
Associate Administrator for Safety Performance Standards.
[FR Doc. 00-13536 Filed 5-30-00; 8:45 am]
BILLING CODE 4910-59-P