From my experience as a Chippie, Radar detectors do work. The thing is, its kinda like someone telling you to duck AFTER you've been shot.
I've cited countless motorists with really expensive detectors sitting on their dash. My buddy swears by his, and its fun to argue about over some beers.
LIDAR (Laser) is our new toy, no real countermeasures that I know of
Best advice is save your money and keep it within 5 mph of the speed limit.
