This article aims to provide information regarding the modification of vehicle exhaust systems for car enthusiasts that love that throaty sound but not when its followed by sirens. There is a noise limit to your vehicle which is enforced by California Vehicle Codes 27150 through 27159.
Here’s a quick summary:
- Any exhaust modifications must not exceed 95 dbA.
- All cars and other motor vehicles must be equipped with a muffler.
California Vehicle Code 27150 reads as follows:
Adequate muffler required
(a) Every motor vehicle subject to registration shall at all times be equipped with an adequate muffler in constant operation and properly maintained to prevent any excessive or unusual noise, and no muffler or exhaust system shall be equipped with a cutout, bypass, or similar device.
California Vehicle Code 25171 defines:
Modification of exhaust systems
(a) No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of the vehicle so that the vehicle is not in compliance with the provisions of Section 27150 or exceeds the noise limits established for the type of vehicle in Article 2.5 (commencing with Section 27200). No person shall operate a motor vehicle with an exhaust system so modified.
(b) For the purposes of exhaust systems installed on motor vehicles with a manufacturer’s gross vehicle weight rating of less than 6,000 pounds, other than motorcycles, a sound level of 95 dbA or less, when tested in accordance with Society of Automotive Engineers Standard J1169 May 1998, complies with this section. Motor vehicle exhaust systems or parts thereof include, but are not limited to, nonoriginal exhaust equipment.
There are additional regulations:
Section 2115.3 prohibits installing “whistle-tip” or other devices that emit a high pitched sound or create a shrieking noise when the vehicle is in operation. Since all exhaust systems on California vehicles require a muffler, the installation of cut-outs or any bypass are prohibited.
While modified exhaust systems are only illegal if they exceed the noise limit of 95 dbA, it’s California smog laws and other legislation that will make your custom exhaust modifications illegal.
“Exercising Their Judgement”
It’s up to a police officer’s discretion to determine if your vehicle’s exhaust noise is over the California noise limit of 95 dbA. This is equivalent to a lawn mower, or a car horn at a distance of 10 feet. The starting point for most factory-installed exhaust systems is 75 dbA, and that includes sports cars.
Assembly Bill 1824:
Allows police officers to issue immediate fines for violating exhaust noise levels.
Prior to 2019, police officers could issue so-called “fix it” tickets. This provided drivers the opportunity to fix their vehicle’s exhaust system within 30 days, provide proof, and avoid paying fines. As of 2019, fines are now mandatory and can range up to $1,000.
Don’t hesitate to contact Ticket Dismissers, if you should find yourself in receipt of a citation involving the modification of your vehicle’s exhaust system, and let us help you avoid the hassle of fines and having your car inspected.