People sometimes ask me if radar gun evidence of their speeding can be successfully challenged in court. Yes, it can. In fact, it can be challenged in several ways. As with other technology-based devices, like Breathalyzers, used by law enforcement, radar guns have to be calibrated for accuracy as recommended by the manufacturer to show the real speed of a vehicle. If the officer cannot provide the calibration record for the specific radar gun used, showing it was within calibration at the moment of the offense, the court may disregard the evidence of speeding.
Florida statutory law gives other ways to challenge the officer's evidence. If the officer using the radar gun had not attended the required course on operation of radar guns, the evidence is inadmissible. It will also be thrown out if the officer, in addition to using radar, failed to make an independent visual determination that the driver was exceeding the speed limit. It is not enough that the gun emits a tell-tale beep for speeding if the officer was reading a newspaper when the driver went by.
Also, if the supposed offender's car is among a pack of cars, preventing the officer from clearly assigning the speed to one specific car, what will happen? The court will refuse to accept the evidence of speeding. The Florida statutes give other ways to challenge the admissibility of the evidence, but they are more technically-oriented. The defenses just discussed are the ones that most people can use without having a technical or legal background.
Of course, one should also consider whether the traffic charge should be contested in the first place. When the time spent going to court is considered, is it really worth fighting the charge? It may be, as long as the officer was wrong about the speeding or if a finding of guilt will result in a much higher insurance premium. Many of the auto accident injuries I handle could have been avoided if people had been driving within the speed limit, so my first advice is drive safely and legally.