California Code of Regulations
Title 13 - Motor Vehicles
Division 2 - Department of the California Highway Patrol
Chapter 4 - Special Equipment
Article 10 - Vehicle Sound Measurement
Section 1047 - Vehicle Sound Level

Universal Citation: 13 CA Code of Regs 1047

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

The measured sound level of a vehicle shall be reported as follows:

(a) Vehicles on the Highway--The A-weighted sound level reading of a vehicle in use on the highway shall be the highest reading observed as the vehicle or vehicle combination passes through the measuring site.

(b) Stationary Heavy Vehicles--The reported A-weighted sound level of heavy vehicles measured when they are stationary shall be the numerical average of the two highest levels that are within 2 dB(A) of each other.

(c) New Motor Vehicles--The sound level reading for new motor vehicles shall be obtained as follows:

(1) Preliminary Runs--Sufficient preliminary runs shall be made to enable the test driver to become familiar with the operation of the vehicle and to stabilize engine operating conditions.

(2) Test Runs--At least four test runs shall be made for each side of the vehicle. When the exhaust outlet is more than 5.1 m (200 in.) from the front of a vehicle with a gross vehicle weight rating of more than 4,537 kg (10,000 lb), at least two runs shall be made for each side of the vehicle using both the primary and secondary vehicle reference points. At least two additional runs shall be made from the reference point that gives the highest readings.

(3) Reported Sound Level--The reported A-weighted sound level for each side of the vehicle shall be the average of the two highest readings on that side which are within 2 dB(A) of each other. The sound level reported for the vehicle shall be the sound level of the louder side.

1. Amendment of subsection (c)(2) filed 11-20-84; effective thirtieth day thereafter (Register 84, No. 47).
NOTE: Editorial correction in Register 79, No. 17 to delete Section 1049, which was repealed as part of Article 10 in filing of 3-26-79 (designated effective 5-1-79).

Note: Authority cited: Sections 23130, 23130.5, 27200, and 38370, Vehicle Code. Reference: Sections 23130, 23103.5, 27200- 27207, and 38370, Vehicle Code.

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