I don't know about the US, but I think we'll have on every major road in 10 years here in Australia. They also do this thing where there are two sets of camera

I don't know about the US, but I think we'll have on every major road in 10 years here in Australia. They also do this thing where there are two sets of cameras, and if your average speed is above the limit between two points your in trouble. At the moment they target heavy vehicles, but my guess its only a matter of time before they target all vehicles.