San Bernardino County, CA Noise Ordinances: Vehicle Noise (2026)

Noise from motor vehicles operating on public roads is largely a matter of California state law, not local ordinance, and the County Development Code expressly exempts 'motor vehicles not under the control of the commercial or industrial use' from its stationary-source noise standards (Section 83.01.080(g)(1)). The governing rules come from the California Vehicle Code, enforced in unincorporated areas by the San Bernardino County Sheriff and the CHP. Vehicle Code Section 27150 requires every motor vehicle to be equipped at all times with an adequate muffler in constant operation and properly maintained to prevent excessive or unusual noise, and prohibits exhaust cutouts, bypasses, or similar devices. Section 27151 prohibits modifying an exhaust system in a manner that amplifies or increases the noise emitted, and provides that for vehicles under 6,000 pounds gross vehicle weight rating (other than motorcycles) a sound level of 95 dBA or less, tested per the SAE J1169 standard, complies. Section 27007 prohibits operating a vehicle sound-amplification system that can be heard outside the vehicle from 50 feet or more while on a highway, except to request assistance or warn of a hazard. Off-road and idling commercial trucks may also be subject to the County's stationary-source standards and to state idling limits.