It picks up signals from other cars being painted. That's why you were told it was being used. Lidar can be used from 4,000 feet away. You'd have no idea you were being painted until your painted. Veil is much more effective. And jammers are illegal in many states and will continue to be banned. LE also knows very easily who is jamming their signal. Since Lidar is only about 20" wide they know what car is jamming them. Which will only draw more attention to you. Detectors against traditional radar are excellent. With Lidar its only detecting when used. And a lot of times its to late. My point is the only way to avoid a speeding ticket is not to speed. The only reason GPS may be helpful is by others with devices pointing out where speed traps are. They can definitely be helpful, but have their weaknesses.