Police use hand-held or vehicle mounted radar units to monitor the speed of vehicles for the purpose of traffic law enforcement. The units are "low power" and have a range of only about one-half mile. The range may be more or less depending upon terrain, weather, and the size of the target vehicle.

Officers must usually be trained and certified to operate a radar unit and to testify in court concerning readings obtained with it.

This guide contains information on how to use these radars properly, when and how they are used and different kinds of radar detectors.