>>If it was really about getting people to slow down, he'd sit out in the open. Instead, he gets one speeder out of many.
The most effective means I have seen to slow down interstate traffic is for a police officer to drive the speed limit in the right hand lane. I've seen people (on a 4 lane interstate) come whipping up in the left-most lane doing 80 (in a 65) and then slow way down when they see the CHP guy in the slow lane.
Had one CHP do about 10 mph under on a particularly stormy evening commute, and I have to say he probably saved some people from skidding off the road.
But you can't gin up revenue that way, as opposed to when you hide behind a billboard with your RADAR gun.
Too bad more states don't have speed trap laws like California's.