what i have found is that the cop will be in court and will “bargain” with you – in exchange for not bringing it to trial, they will drop the charges down to a lesser amount of speeding, or if you were already not speeding too too fast they’ll drop to a non-moving violation, like failure to wear a seatbelt. that way, the town that the ticket is from gets money out of you, but they get to save on not having a trial and the time of the officer, judge, court staff, etc., and you get to just pay a fine but not have your insurance go up.
i am good friends with a cop and he told me when he has to appear for a trial about speeding, the first thing he has to do in his testimony is talk about how long he has been a police officer and all the trainings he has had, listing them by class title, year, etc. so that he is shown to be very competent right off the bat at assessing speeds. then he does his testimony about what he saw. the speeder does his testimony, which is basically just saying he did not speed, which sounds comparatively lame. and then the judge may drop the charges to a lesser charge, which the speeder could have gotten in the original bargaining session, plus saved himself time and lawyer’s fees, or the judge could make the charges stand, in which case the speeder wasted his time and is found guilty anyway, and i’m sure in very rare instances the judge will dismiss the ticket (but very rare because 1. tickets bring in revenue for a town and 2. if the judge does that too much it will discourage officers from doing their jobs, namely, catching traffic violators like yourself).