back in the 70s my brother had a 1935 internatinal pickup built into a street rod headers comming out just behind the front tires with pipes runnung down the edge of the running boards and he got a ticket for modified exhaust fine was only like 10 bucks back then they didn't usally inforce but he pissed off the depudy.
I believe there is but from my experience it’s only enforced as an excuse to pull someone over for suspicion of something else or to add to other charges. The number of loud motorcycles, diesels, rice burners and muscle cars I see tells me it isn’t being enforced.