I had an argument with my brother the other day, over the accuracy of police radar. We're both former Troopers, though in different states, so we both have experience on the giving end of speeding tickets. In his state, moving radar was not allowed, because the department believed it did not give accurate readings of vehicle speed. In my state, many a town's coffers were filled by moving radar and no one ever mentioned that it might not be accurate. (Moving radar is nothing more than a radar unit mounted inside a moving patrol car, designed to read the speed of oncoming -and sometimes overtaking- vehicles.)
Our argument was about angles and errors. My brother's point was that radar is only accurate if it's stable (mounted on a fixed platform) and has a very slight angle to the target, approaching zero degrees. "Posh," said I. I wrote approximately a gazillion tickets from moving radar (just like this one) and it works just fine. Well, maybe it doesn't.
As a practical matter, I don't think there's a problem with police use of radar, moving or otherwise. Most Troopers won't even stop a car unless it's going 15 over the limit, so errors of 1-5 mph are unlikely to be netting "innocent" motorists. Also, Troopers can often tell when the radar is giving a spurious reading, and they ignore it. But with speed cameras, it's a different story. Given the lack of judgment, the lack of discretion, and the camera-owners' inherent bias toward lowering the speed at which the machine issues a ticket, the damn things should be abolished.
Oh, and if you're one of the people to whom I wrote a ticket that was maybe a little a higher than it should have been, I'm sorry about that. Get a better radar detector.