Just watched a report on the news today that the city of West Hollywood, Cali. is adopting a strict vehicle noise law. This is primarilly being enacted to stop noisy motorcycles (Harleys et al) that frequent the Sunset strip, which runs from L.A. into and thru W. Hollywood.
My belief is that this will shortly lead to vehicles of all types being profiled for noise. There are lots of celebs and a lawyer or 3, that ride Harleys, Ninjas, good sounding P cars and very loud Lambos--that will get fix it tickets.
Check out the law at the State level (VC 27151) at www.bobsmuffler.com/noise.htm
The state's laws are not bad...and tend to favor the motorist in the noise test area. I don't know how W. Hollywood Deputy Sheriffs can conduct an unbiased Db test on the street. That city is weird, and has laws for Medical use of pot , and laws for cats claws