Radar detectors have become very popular over the last four decades. For many people, radar detectors are the only thing that is between them and multiple speeding tickets. Before you drive like Mario Andretti you might want to find out how radar detectors work.
Police officers have been using radar guns for more than 30 years. A radar gun has a radio transmitter and receiver combined. The transmitter transmits the electromagnetic wave through the air. The receiver picks up the electromagnetic waves with an antenna. Radio waves move at a constant speed. Since these waves move at a constant speed the echo that bounces back off of your car is used to measure the distance between the radar gun and your vehicle. As your vehicle moves the distance changes. The radar gun is able to tell how fast your vehicle is moving by the changes in the distance over time. Radar guns can even be used in moving police cars. The speed of the police car is determined by the gun included in the formula to determine the speed of the offending vehicle.
Recently a new type of speed detector using light instead of radio waves has been adopted by many police departments. These are called Lidar Guns (Light Detection and Ranging). Police use these guns often in small, handheld, versions along with cameras. In fact, many cities are installing fully automated Lidar guns at busy corners and on traffic lights. These Lidar guns have cameras that photograph the license plate and the driver. Speeding tickets are then sent through the mail.
Having a basic radar detector in your vehicle is one way of preventing speeding tickets. Radar detectors are setup to pick up specific frequencies and alert you to the possibility of radar guns. People who use radar detectors to keep from getting speeding tickets are warned when radar guns are detected in the area that they are traveling in. Usually, police officers have their radar guns on for long periods of time before the target a vehicle. However, it is possible to have police officer drive up behind you and turn on his radar gun at the last minute, just before he pulls you over. When this happens conventional radar detectors aren't much help.
Modern radar detectors are more proactive than the conventional radar detectors. Modern radar detectors include jamming signals. Jamming signals make it difficult for radar guns to read the signals that are bouncing back to them by adding radio interference. This keeps police officers from being able to tell how fast vehicles are moving. Another feature modern detectors include is a light sensitive panel. Light sensitive panels detect beams from Lidar guns. Unfortunately, by the time light sensitive panels are able to detect the beams and it's often too late.
Laser jammers are also available which works basically like the radar jammers in that they jam the laser signal making it difficult for police officers to tell the actual speed of the vehicle. As technology improves police officers are finding more and more ways to catch speeders. The best way to prevent getting any speeding tickets is to slow down.