The Lowdown on Lidar
Speed radars are good for speed traps, but not so great to prevent speed related incidents. They share the same fatal flaw with all other single-point speed meters: You can just slow down for a minute, while you pass by the speed trap, and then speed up for the rest of your trip. Instead, a 2-point speed meter (i.e. license plate readers every few miles, measuring time between matching reads) system is superior because a) their margin of error is negligible and b) they measure sustained speed over a long distance rather than at a single hot spot, thus making roads safer. I can't believe it's not implanted at least in all interstate freeways.