actually I think that ambulances and some cop cars have those sensors... I remember reading about a guy who somehow got his hands on one and drove to work in a few minutes, making all lights along the way- he eventually got busted because people monitoring the power grid noticed a pattern and it was not a cop...- I know you're-squirtdad- probably posting this as just a funny idea, but obviously realistically drivers would probably not be too happy... just a thought