Yes, it's worse when drivers of large, heavy vehicles are stupid. They're more dangerous. But I don't know that they're stupid more often than cyclists or pedestrians. When passing school and college campuses at commute time I see a lot of insane behaviour on the part of cyclists and pedestrians. Some seem to feel they're immune to the laws of physics! Or maybe it's that they feel they're so flexible in traffic that they can get away with anything. It's scary to drive a car at such times, or to be a pedestrian amongst the cyclists.

I've also encountered a few cyclists who are downright nasty. Other day I was at a demo, holding a sign saying "Defend the Constitution" and a cyclist riding by gave us all the finger and shouted "Traitors!" Hmmm. How'd he figure that? Defend the constitution = treason? Oh well. Somehow we expect more of cyclists than of drivers, but maybe we shouldn't.