simple solution to this
make safety mandates and apply them too, also make specific emmissions laws (not just slapping a cat on a POS engine), Once applied correctly 95% of the problems of traffic will solve.
e.g. - if you are driving a welded up POS with "aasum engin svap" like toyota 1UZ- V8 into a suzuki FX, your car gets impounded and crushed.
You remove the cat converter and install muffler in place - your car gets impounded, your car not passing OBD inspection - you get to pay a 5 figure fine.
same with motorcycles, your bike does not have full cycle parts or is missing safety mandates like lamps and gauges, it gets impounded.