At what point is radar gun evidence legitimate in court?

A police officer used a radar gun to clock me speeding from 808 ft away. Is that within the legal margin?

Asked on June 15, 2016 under General Practice, Illinois


SJZ, Member, New York Bar / FreeAdvice Contributing Attorney

Answered 4 years ago | Contributor

There is no hard and fast cut-off. A radar gun will work out to 808 feet away, and even further, for example. However, what happens is that the radar beam "spreads" as it travels, and at that distance, is wide enough to take in or capture multiple vehicles at once; therefore, if there were a number of vehicles around, in front, behind, etc. you in proximity, the gun could have clocked someone else, not you. You may be able in court to cast sufficient doubt on the speed reading on this basis IF there were other cars around you. If you were essentially the only one on the road at that point, and everyone else was hundreds of feet away, however, this argument will not avail you.

IMPORTANT NOTICE: The Answer(s) provided above are for general information only. The attorney providing the answer was not serving as the attorney for the person submitting the question or in any attorney-client relationship with such person. Laws may vary from state to state, and sometimes change. Tiny variations in the facts, or a fact not set forth in a question, often can change a legal outcome or an attorney's conclusion. Although has verified the attorney was admitted to practice law in at least one jurisdiction, he or she may not be authorized to practice law in the jurisdiction referred to in the question, nor is he or she necessarily experienced in the area of the law involved. Unlike the information in the Answer(s) above, upon which you should NOT rely, for personal advice you can rely upon we suggest you retain an attorney to represent you.