so where I live we don't have many speed cameras, we have little flashing signs that show you your speed, if your speeding you get a sad face flash at you, if you then slow down before you reach the post you get a big smiley face and a little note says happy driving.
These seem to work very well. As it's nice to get a smiley face.
The police wait on the long country roads with speed traps as normal, but if your speeding they pull you over and you have an instant fine. We do not have a high failure to stop rate, virtually zero as the police carry guns. So no stop get shot is the phrase.
What's it like where you live.