Norwalk, CA Noise Ordinances: Vehicle Noise (2026)

150(D), part of Article III's list of Particular Acts, prohibits discharging the exhaust of any steam engine, stationary internal combustion engine, motor boat or motor vehicle into the open air except through a muffler or other device that effectively prevents loud or explosive noises. That standard reaches modified exhaust systems on cars and motorcycles as well as loud stationary engines and boat motors; an exhaust altered to be louder than what a proper muffler produces falls within the prohibition even without a specific decibel reading.

150(I) separately addresses driving behavior rather than equipment: racing the motor of any motor vehicle, or needlessly bringing it to a sudden start or stop, is independently unlawful, covering revving and aggressive launches even where the exhaust itself is stock. 130, giving enforcement officers both a specific equipment standard and a specific conduct standard to cite. Norwalk contracts with the Los Angeles County Sheriff's Department, whose deputies handle traffic and noise enforcement citywide, including citations for modified exhausts and racing.