But not based on decibels but just any non oem addition for exhaust. Seems to me that if the exhaust meet standards this is imho discrimination because they do not target automobiles with aftermarket exhaust.
Actually, I think Denver too has the standard that an exhaust be stamped with an EPA marking. An after-market exhaust maker could technically get theirs certified, but it's just cost effective to do so. And one of the reasons jurisdictions do the EPA stamp thing is because of the inconvenience and expense of having to outfit every cop with a certified decibel meter or if they have one for a department to get that meter to the scene.
In fact, I have a possible solution! Make it part of the law that jurisdictions use decibel meters with a reasonable standard AND that part of the ticket revenue they generate goes to buying jurisdictions decibel meters to enforce it.
That way word gets out that loud pipe riders end up paying for the very equipment that is going to nail them. Meanwhile, reasonable level after-market pipe riders don't get popped.
Whaddya think? If I were a legislator I'd find that an attractive option.