I never did get it.

Whats the point?

If i'm "speeding", 9 times out of 10 I know I'm going over the speed limit. I don't need a sign to validate the obvious, I DO have a speedometer.
I see people speed pass them all the time, ignoring "your speed".

How many people slow down when they see one of these radar speed signs? I always saw them as a waste of tax dollars, lol.