I don't see too many benefits with the rule. Rather, it will tell greatly on humans, their mobility, and productivity.
Like you, I always assumed that the industries that release all of their waste to the air and vehicles that are in poor conditions yet work the roads are responsible. I'm surprised by this aspect.

The thing is, the rule will do more harm. After all, families would have to overwork their cars, and in the end, the cars will begin to release more fumes than it would if It had to do less work.