Plumas County, CA Noise Ordinances: Vehicle Noise (2026)

Plumas County does not have its own on-road vehicle-noise ordinance; motor-vehicle noise on highways and public roads is regulated by California state law, which preempts local rules for vehicles in motion. California Vehicle Code Section 27150 requires that every motor vehicle subject to registration be equipped at all times with an adequate muffler in constant operation and properly maintained to prevent excessive or unusual noise, and prohibits any muffler or exhaust system with a cutout, bypass or similar device. Section 27151 prohibits modifying a vehicle's exhaust system to amplify or increase noise beyond legal limits. Under the Vehicle Code's noise-limit provisions, exhaust systems on most vehicles under 6,000 pounds (other than motorcycles) comply at a sound level of 95 dBA or less, measured per the SAE test standard at 50 feet, and motorcycles have their own limits by model year. The County's General Plan recognizes roadways (State Routes 70, 89, 36, 147 and others) and railroads as dominant noise sources and manages adjacent land use through CNEL noise contours rather than citing passing traffic. Vehicle-noise enforcement falls to the Plumas County Sheriff and the California Highway Patrol.