I've just been cited 65+ in a posted 55. Since the trooper was using radar and I was in traffic, I figure I stand a reasonable chance.

Dunno about your state, but if it's anything like CA, they use relatively narrow-beam KA band radar and document it on video tape with a crosshair and speed-readout overlay. When you see the tape, it's pretty clear that they nail you fair and square.

However. If for some reason the radar unit requires calibration (they used to in the old days, dunno about lately) and the cop can't provide the paperwork in court proving it was calibrated, then the ticket will be thrown out.

Sometimes you can simply try to take it to court, and if you're lucky the cop won't be able to show up that day (or won't want to miss the work, just to waste time prosecuting a piddly 65-in-a-55) and the ticket will get thrown out.

You could go in for the initial hearing, plead no contest, admit your speed, and ask for a sentence reduction based on the fact that 65 in a 55 wasn't dangerous for the conditions at the time and you were going with the flow of traffic (assuming that's really what you were doing). Just don't say that the clocking was wrong unless you really intend to contest the clocking at a trial, and don't say you didn't know how fast you were going because they'll throw the book at you if you say that (if you don't know how fast you were going you're not driving safely, says their reasoning).

Your final option is to pay a lawyer to help you contest the ticket. Didn't someone link an article recently about the lawyer who specialized in getting people out of speeding tickets?

Oh, and your refusal to sign the ticket doesn't mean jack.