Transmitter/receiver system for limiting speed of vehicles, comprises fixed or mobile transmitters of frequency modulated coded signals and receivers in vehicles which limit speed according to code

摘要

Coded frequency modulated signals from a fixed station are received by vehicles in a zone and the vehicles are slowed to a required speed despite any attempt to accelerate. Beyond the zone a further fixed signal releases the limitation or imposes a different speed limit. The use of two stations may be avoided by imposing speed limits for fixed times or distances. Portable transmitters may be used for emergencies or arrests