In light of some of the posts on this thread, I just wanted to share a story.
Last week I was driving on the Southeast Expressway in Boston doing 70mph in the high speed lane in heavy traffic conditions (pretty much the norm for Boston drivers; in fact that might be considered slow and you will likely be passed by many at that speed).
Someone came flying up on my bumper, tailgated for a bit, then decided, apparently, that I wasn't going fast enough for his or her liking and shot out around me into the middle lane, then jumped over to the right lane and flew ahead in that lane for a while, shooting way up ahead until I lost sight of it. He or she had to be going at least 80+, way faster than me.
Imagine my surprise when I saw it was someone in a Smart Car!

I'd never seen one of those move so fast, and admittedly I did worry about the driver if there was an accident. I never saw who was driving.