I see cars as a pollutant, but the EPA needs more strict regulations on emissions on vehicles like freight, dump trucks and other larger vehicles. You see them spewing exhaust and back smoke on a regular basis. Also I think police should be able to pull someone over who has black or nasty smoke coming out of their car and give them a warning to get it checked out. It is bad enough we breathe it in during traffic, we don't need it to be worsened.