Here's SEMA's recommended regulation:
Quote:
SEMA Exhaust Noise Model Bill
No person shall modify the exhaust system of a motor vehicle in a manner so that the exhaust system emits in excess of ninety-five decibels as measured by the society of automotive engineers (sae) standard j1169 (may 1998). It shall not be a violation of this section unless proven by proper authorities that the exhaust sytem modification results in noise amplification in excess of ninety-five decibels under the prescribed sae test standard.
A court may dismiss any action for which a person is prosecuted for operating a vehicle in violation of this subsection if it is found that the defendant had reasonable grounds to believe that the vehicle was not operated in
The term motor vehicle as used in this section does not include motorcycles.