Vehicle Noise: Brentwood vs Oakley
How do vehicle noise rules compare between Brentwood, CA and Oakley, CA?
Brentwood and Oakley have similar restriction levels.
Brentwood, CA
Contra Costa County
Vehicle noise in Brentwood is regulated primarily through California Vehicle Code §27150 (adequate muffler) and §23130 (decibel limits), enforced by Brentwood Police. Modified exhaust, engine revving, and audio systems audible at 50 feet can result in citations and fix-it tickets.
View full Brentwood rules →Oakley, CA
Contra Costa County
Oakley enforces California Vehicle Code Section 27150 requiring adequate, unmodified mufflers on all vehicles, along with OMC Chapter 8.20 prohibitions on excessive vehicle noise. Modified exhausts, engine revving, and audio systems audible 50+ feet away from the vehicle are all subject to citation.
View full Oakley rules →Key Facts Comparison
| Fact | Brentwood | Oakley |
|---|---|---|
| Muffler requirement | CVC §27150 | CVC 27150 – adequate muffler |
| Motorcycle limit | 95 dBA (CVC §23130) | - |
| Car limit | 80-86 dBA | - |
| Audio system | Audible at 50 ft = violation | - |
| Typical penalty | Fix-it ticket + $25 fee | - |
| Max dBA | - | 95 dBA (CVC 27151) |
| Stereo limit | - | Audible <50 ft (CVC 27007) |
| First fine | - | $100–$200 + fix-it |
| Sideshow | - | Impoundment possible |
Highlighted rows indicate differences between cities.
Brentwood FAQ
Is aftermarket exhaust legal in Brentwood?
Only if it complies with CVC §27150 (adequate muffler, no cutouts/bypasses) and keeps total vehicle noise under the CVC §23130 limits. Straight-pipe and whistle-tip setups are not legal on public streets.
Can I be cited for loud bass from my car stereo?
Yes. CVC §27007 makes it an infraction to operate a sound amplification system that is audible at a distance of 50 feet or more from the vehicle.
Oakley FAQ
Are aftermarket exhausts ever legal in California?
Yes, if they are CARB-approved and do not exceed the 95 dBA limit. Many aftermarket systems meet these standards, but straight pipes and cutouts do not.
Can I be cited for revving my engine in my own driveway?
Yes. Oakley Municipal Code Chapter 8.20 prohibits unnecessary vehicle noise regardless of whether the vehicle is on private or public property, particularly during quiet hours.
What about diesel trucks with loud engines?
Stock diesel trucks generally comply, but "delete" modifications that remove emissions equipment typically also violate noise and CARB regulations, with significant fines possible.
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