I just do my best to ignore them all. Not always easy, but I try. There is no real solution....
Except maybe a device that sprays nasty black oil or tar out of a not so conspicuous area, like the tail pipe, at a 45 degree angle so as to coat their windshield, causing them to have to pull over and clean it off because their wipers just smeared it up real good. But that could cause further problems.
