I don't know what it is, but there are 3 different radar sites on my way to work (the stand up ones that have the speed limit sign on them and show you your speed as you pass), all of them have one on each side of the road but NONE of them ever get my speed, is the design of the cladding and shape REALLY designed to "fly" under the radar, lol It's weird, I can see every vehicle up ahead of me get picked up but when I go by (even if I am the only one and have plenty of distance from the front vehicle), I get nothing. Not really upset about it lol, just thought it was weird