i am curious wrote:
If he used a radar gun, you have some options. For one, question the last time the radar gun was calibrated, and at what error was it showing at last calibration. Take a picture of where you were pulled over. Was it around a curve? Speeds can show faster on a gun for a car going around a curve. Anyway, here is a site to give you more information.
http://www.worldlawdirect.com/article/903/fighting-speeding-ticket.html
In my state, and I assume all others, all that is needed is that the cop say he was using the radar gun, or VASCAR or a laser etc. The prosecution gets a presumption the device works. I don't even have to ask if it was calibrated, though I do. They always are at the beginning of each shift.
It will be up to YOU to prove the gun was faulty. You won't be able to do that.