The officer has already seen the black box glued to the windshield or visor--they LOOK for it. By the time he's behind you its too late. The Belmont radar cop looked at me as I drove by him the other day--I was at the residential speed limit & the V-1 wasn't even on! If he pulled me over I would have reached up & turned it off so it isn't flashing & beeping. That's annoying. right on your windshield???