Tustin, CA Noise Ordinances: Vehicle Noise (2026)

On public streets and highways, vehicle noise in Tustin is primarily a matter of state law rather than a city decibel ordinance. California Vehicle Code Section 27150 requires every motor vehicle to have an adequate muffler in constant operation to prevent excessive or unusual noise, and Section 27151 prohibits modifying an exhaust system to amplify or increase noise beyond legal limits; for passenger vehicles under 6,000 lbs the SAE test threshold is 95 dB(A). These statewide rules are enforced by the Tustin Police Department through traffic stops. The Tustin City Code's noise chapter (Chapter 6) does not assign separate decibel ceilings to passing vehicles, but 'mobile noise sources' and property-based vehicle activity (such as idling delivery trucks, loading, or vehicle repair) on a parcel remain subject to the Section 4614 exterior standards for the applicable noise zone. Construction-related delivery and equipment vehicles are additionally barred outside approved construction hours under Section 4616(2). Owner-performed repair of personal property on one's own residential lot is exempt 7 a.m.-9 p.m. under Section 4617(l).