Grass Valley, CA Noise Ordinances: Vehicle Noise (2026)

For vehicle and motorcycle noise, the County of Nevada (California) relies on California state law rather than a unique county decibel ordinance. General Plan Noise Element Policy 9.1.16 states the County will 'minimize the noise impact from automobiles, trucks, motorcycles, and off-road vehicles by continuing to request enforcement of those sections of the California Vehicle Code relative to vehicle exhaust system maintenance by the County Sheriff and State Highway Patrol.' California Vehicle Code Section 27150 requires every motor vehicle to be equipped with an adequate muffler in good working order to prevent excessive or unusual noise, and Section 27151 prohibits modifying an exhaust system to amplify noise; related provisions limit excessive vehicle noise. The County also encourages routing heavy truck traffic away from residential areas (Policy 9.1.7). Stationary vehicle noise on private property (for example, idling equipment or off-highway vehicle use affecting a neighbor) can additionally fall under the General Plan exterior noise standards. Roadway and traffic noise is otherwise addressed through land-use planning and mitigation rather than direct enforcement against individual drivers.