STella, what I don't understand is how they manage to get the cigarette lit, let alone smoke the whole thing.
As soon as you hear the match or the lighter flick, you should be saying there is no smoking in this car, and when they butt it out, you should inform them if goes out the window. You might even say, I'll pull over so you can toss the cigarette outside.
I'm with Al-Gebra on this one. I know it's blaming the victim, ...but you got it coming.