[jims69camaro]

also known as the "accordion effect": when the traffic slows, everyone bunches up, following closely behind the person in front of them. then, once traffic opens up again, the distance between cars increases. watching it from a helicopter really puts those "spots" in perspective. and an accident is even worse, since both directions of traffic slow down to "rubber-neck" and see what's going on.

btw, anticipating the other driver's course of action is called defensive driving. imagine the worst possible thing that any driver on the road might be able to do and you'll end up on the receiving end of an accident that much less. no one can prepare for or avoid getting hit from behind. that has to be the worst feeling in the world...