Santa Cruz County, CA Noise Ordinances: Vehicle Noise (2026)

Vehicle noise splits between two regulators. On public streets and highways, the State of California controls. California Vehicle Code Section 27150 requires every motor vehicle to have an adequate muffler in good working order and prohibits modified exhaust that amplifies noise; Section 27151 bans exhaust-system modifications that increase noise; and Section 23130 sets vehicle noise-emission limits by speed and vehicle type. The County General Plan acknowledges this preemption, stating the County 'has no direct control over noise produced by trucks, cars and trains because state and federal regulations preempt local laws.' For vehicle activity on private property and off-road, however, County Code Chapter 8.30 applies: the General Plan confirms the County Noise Ordinance addresses nuisance violations including 'vehicle repair and testing' and 'powered motor vehicles' used in a manner inconsistent with the ordinance. Such activity is judged against the Chapter 8.30 thresholds (75 dB or discernible 150 feet by day; 60 dB or discernible 100 feet at night). For on-road noise complaints (loud exhaust, racing), contact the Sheriff's Office or CHP, which enforce the Vehicle Code.