Merced, CA Noise Ordinances: Vehicle Noise (2026)

Merced does not regulate motor-vehicle exhaust or engine noise through its Municipal Code; there is no city muffler standard or street-racing-noise decibel rule. Instead, on-road vehicle noise falls under the California Vehicle Code, which the police enforce statewide and in Merced. Vehicle Code 27150 requires every motor vehicle to have an adequate muffler in good working order to prevent excessive or unusual noise, and Vehicle Code 27151 prohibits modifying an exhaust system to amplify or increase noise beyond legal limits; California also references SAE J1492/J1169 sound-level test standards for enforcement. These are state offenses, typically correctable 'fix-it' citations, not Merced ordinance violations. The one vehicle-noise topic Merced does codify is commercial: under MMC 10.12.154, no one may operate an advertising vehicle equipped with a sound-amplifying or loudspeaker device on city streets without a permit from the City Council. Excessively loud car stereos at a fixed location (e.g., parked at a residence or party) can also be reached through the Disruptive Parties chapter (MMC 9.64) or as a nuisance. Residents bothered by loud exhausts or stereos on the road should report them to the Merced Police Department as a Vehicle Code matter.