Police have long used radars to track the speed of drivers and to help maintain safe roads. Meanwhile, many drivers have begun using radar detectors to help avoid costly fines for speeding violations. Despite the popularity of radars and radar detectors, many people do not understand the science or technology behind them.Police radar guns work by transmitting radio waves from the radar to the target vehicle and back. Because radio waves move through the air at a constant speed (the speed of li.