D.C. Mun. Regs. tit. 20, r. 20-2811
No person shall operate a motorcycle, motor vehicle, or combination of motor vehicles of a type subject to registration under D.C. Code § 40-103 (1990 Repl. Vol.) at any time, or under any condition of grade, load, acceleration, or deceleration in a manner that exceeds the maximum noise limits designated in the table of this subsection for the specified speed limits, measured at a distance of fifty feet (50 ft.) from the center line of travel by a sound level meter switched to the A-weighting network, in accordance with such nationally recognized test procedures as the administering agency may prescribe in accordance with §§ 2700.7 through 2700.9 of Chapter 27 of this subtitle.
TYPE OF VEHICLE | NOISE LIMIT | ||
35 MPH or less | Over 35 MPH | Stationary Run-up | |
Any motor vehicle with a manufacturer's gross vehicle weight rating of ten thousand pounds (10,000 lbs.) or more, and any combination of vehicles towed by that motor vehicle | 86 dB(A) | 90 dB(A) | 88 dB(a) |
Any motorcycle | 82 dB(A) | 86 dB(A) | |
Any other motor vehicle and any combination of vehicles towed by a motor vehicle with a manufacture's gross weight rating of ten thousand pounds (10,000 lbs.) or more | 76 dB(A) | 82 d(B)(A) | |
Where a test procedure is used for which the noise levels prescribed in the table in § 2811.1 would not be appropriate, the administering agency may establish and publish a table with the appropriate levels which are substantially equivalent to those established in that table.
The public shall be provided with at least thirty (30) days to comment on all new standards and procedures before the standards are made final.
For the purposes of this section, a motor truck, truck tractor, or bus that is not equipped with an identification plate or marking that bears the manufacturer's gross vehicle weight shall be considered as having a rating of ten thousand pounds (10,000 lbs.) or more if the unladen weight is more than nine thousand pounds (9,000 lbs.).
No person shall operate a motor vehicle equipped with an engine speed governor that generates a sound level in excess of eighty-eight (88) dB (A) measured on an open site with a fast meter response at fifty feet (50 ft.) from the longitudinal center line of the vehicle when its engine is accelerated from idle to a wide-open throttle governed speed with the vehicle stationary, transmission in neutral, and clutch engaged.
The administering agency may by regulation prescribe correctional factors to the limits prescribed in the table of § 2811.1 of this section when measurements are made at a site that contains large reflecting surfaces in close proximity to the vehicle or noise measuring microphone.
A violation of the adjusted levels as provided in § 2811.6 shall constitute a violation of this section.
In the event that it is impractical to obtain a measurement fifty feet (50 ft.) from the center line of travel, the actual distance shall be measured and one (1) of the correctional factors in the following table shall be applied to the maximum permissible sound levels prescribed in the table of § 2811.1 of this section.
DISTANCE | CORRECTION | |
Soft site | Hard site | |
35 - less than 39 ft. | +3 dB(A) | +5 dB(A) |
39 - less than 43 ft. | +2 dB(A) | +4 dB(A) |
43 - less than 48 ft. | +1 dB(A) | +3 dB(A) |
48 - less than 58 ft. | 0 dB(A) | +2 dB(A) |
58 - less than 70 ft. | -1 dB(A) | -1 dB(A) |
70 - less than 83 ft. | -2 dB(A) | 0 dB(A) |
For the purposes of this section, "soft test site" shall mean any test site having the ground surface covered with grass, another ground cover, or a similar absorption material for one-half (1/2) or more of the distance between the microphone target point and the microphone location point.
For the .purposes of this section, "hard test site" means any test site having the ground surface covered with concrete, asphalt, packed dirt, gravel, or similar reflective material for more than one-half (1/2) the distance between the microphone target point and the microphone location point.
D.C. Mun. Regs. tit. 20, r. 20-2811