I tell you what, take 4 kids each from two different bus stops located on heavily traveled roads.
One group is affected by "car exhaust" the other group is stoned.
Test them as soon as they arrive at school on a variety of subjects. Math, Science, English , etc.
Are you saying the group affected by car exhaust is going to test the same as the group high on weed ?
See how ridiculous your argument is ?
Jesus H, just go away. If that the extent of your argument for legalization then youv'e lost.
And yea it cost money to enforce laws. Big deal.