Vehicle Noise: Daly City vs South San Francisco
How do vehicle noise rules compare between Daly City, CA and South San Francisco, CA?
Daly City has fewer restrictions than South San Francisco.
Daly City, CA
San Mateo County
No Daly City-specific ordinance directly addresses vehicle noise; California Vehicle Code defaults apply, requiring adequate mufflers on all registered vehicles and prohibiting car sound systems audible 50 or more feet away on a highway.
View full Daly City rules →South San Francisco, CA
San Mateo County
Noise from motor vehicles operated on public roads in unincorporated San Mateo County is primarily controlled by the California Vehicle Code, which requires an adequate muffler and prohibits modified exhaust that amplifies noise. The County's Chapter 4.88 noise limits generally address stationary, on-property noise rather than vehicles in transit on public rights-of-way.
View full South San Francisco rules →Key Facts Comparison
| Fact | Daly City | South San Francisco |
|---|---|---|
| Local vehicle-noise ordinance | None; state law applies | - |
| Muffler rule | Required, no cutouts (CVC 27150) | - |
| Car stereo limit | Not audible at 50 feet (CVC 27007) | - |
| Enforcement | Police traffic citation | - |
| Primary authority (roads) | - | California Vehicle Code |
| Muffler requirement | - | Veh. Code 27150 |
| Modified exhaust | - | Veh. Code 27151 |
| Enforced by | - | Sheriff / CHP |
| On-property revving | - | County Code 4.88.350 |
Highlighted rows indicate differences between cities.
Daly City FAQ
Is a loud car stereo illegal in Daly City?
Yes, on any street. Vehicle Code 27007 bars operating a sound system audible 50 or more feet from the vehicle on a highway, except to request assistance or warn of a hazard.
Are modified loud exhausts legal?
No. Vehicle Code 27150 requires an adequate, properly maintained muffler preventing excessive or unusual noise and prohibits cutouts, bypasses, or similar devices on registered vehicles.
South San Francisco FAQ
Does the county have its own vehicle-noise decibel limit?
For vehicles on public roads, the California Vehicle Code controls. Sections 27150 and 27151 require an adequate muffler and prohibit modified exhaust that increases noise; these are enforced by the Sheriff and CHP.
What about a loud car idling or revving on a driveway?
Vehicle noise made on private property that disturbs neighbors can be addressed under the County's General Noise Regulation (4.88.350) in addition to any Vehicle Code violation.
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