From my post it seems very clear that a muffler is required on motor vehicles in Calif. The sections of of the code posted are the ones which carry a citation for violation. Getting by without one is not the same as being legal. <br><br>

 

Are "Big Rigs" required to have mufflers? Dont they just run straight pipes going up?

 

Yes, all on-road trucks are required to have mufflers, if not by state law then by federal law. It's a violation of federal law (Noise Control Act of 1972) to "remove or render inoperative" any noise control part on a vehicle with a GVW over 10,000 pounds made after 1972 and then operate the vehicle on the road. Mufflers aren't the only thing covered by this law, the air cleaner is usually a noise control part too.