A French town on the outskirts of Paris Orly airport has begun tackling loud motorcycle exhausts, by installing a 'noise radar' capable of identifying the offending vehicle, pinpointing their location...
Something you don't have in the US but that Europe has in spades are shagged out old 2 stroke mopeds that can be ridden by 16 year olds (sometimes younger) with no licence.
The same system is used in the USA to track gunshots.