[OJFord]

> I've never understood why, if speeding is such an important thing to prevent, why don't they use camera enforcement. If you travel between cameras A and B in less than the minimum time it would take at the speed limit, somewhere along the way you were speeding.

I don't know about the US, and I suppose it varies between states anyway, but in the UK that's exactly how it works on our motorways and some larger dual carriageways.