A radar laser detector (although separately known as a radar detector and a laser detector) is commonly used by motorists to see if their speed is being spied on by some radar unit. Simply put, the police would "shoot" a radio wave to the moving vehicle with a radar gun, and the speed would be calculated using the principles of the Doppler Effect.

In addition, recent speed detectors have evolved into using the laser technology. Also known as LIDAR (Light Detection and Ranging), it uses pulsed laser instead of the old radio waves. Therefore, modern radar detectors have also evolved now to be alert to infrared light sent out by the devices such as the LIDAR guns. Although the technique itself seems great nominally, it is not as effective as the old school radar detection technique because the beam that is sent out is relatively focused. Unlike the radio waves which can scan a width of 85 feet across at 1000 feet from the originating source, LIDAR's beams can only expand a mere 6 feet. As most of the beams are usually targeted in the middle, there is a chance that the detection might fail as the radar detectors are usually mounted at the side, away from the aim of the beam. In addition, LIDAR detection is not as widely used because of the high price compared to the old radar equipment and because an officer cannot be using it in motion, as he or she needs to target the moving vehicles one by one. Nonetheless, the focused beam allows the officers to target both close and distance objects, as LIDAR beams can shoot up to 3000 feet.Radar Laser Detector

A Word of Caution

It is important to note that equipments that absorb radar and laser detection waves are illegal, as it can jam the radar equipment.