The officer is only required to produce evidence at your trial, and not at the time the citation is being issued. At that time, you may scrutinize his evidence to your heart's content. However, you are NOT required to prove you were not speeding. The burden of proof falls upon the officer on behalf of the state, as to proving your guilt. Every man, woman, and child accused of a crime in these United States of America is considered innocent until proven guilty in a court of law. The person who answered that you will have to prove you were not speeding is, unfortunately, incorrect.Footnote: When running radar, I never lock in the offender's highest speed. I continue the track the offending vehicle for as long as possible to verify to myself, as well as the court, that I am indeed tracking the correct vehicle. Locking in the speed would remove supplementary evidence that could assist me in proving my case. I'm sure the officer who issued your citation may have had similar reasons. You will certainly find out at your trial, if you choose to have one. Good luck.