But what about those dead-obvious stripes on the road?

I've been thinking about hanging a piece of black carpet from the back of my car, with the same graduation lines, only spaced differently. Thus, I can go past a speed camera at 90mph, but when they look at the film, it'll only appear that I was doing 25mph .

Oh, and they often have the lines painted on the road where there's no camera, as well.