radar detectors operate by sending a never ending beam of radar in the direction the vehicle is facing. at the point of which you nice new vehicle and girlfriend come into the beam it calculates the time it took the beam to come back to the police vehicle( which is all done in hundredths of a second) there are three types of radar, x band, k band, and ka band, most departments have gone to the ka band which returns signals in much faster time, it can also check the speed of the car ahead of you even if youre driving in the same lane or meeting. the one in rear picks you up as you approach or pass the police car. The only time a radar detector is usefull is if the cop has just been sitting in the same spot for a long time and not looking when your speed showed up, that gives you a chance to slow down before he does look. If you do get pulled over then immediately take it off the vehicle and throw it under the seat, seeing it will only cause a ticket more likely to be written, if they are using lidar that means they are aiming a gun that shoots a lasar at your vehicle and gives them an instant reading, no beating that, only downfall is the officer must be parked to use it. So to sum this up radar detectors are a scam and cannot beat any current radar or lidar. hope that helps