An anonymous reader writes with news of a device built by a company in the U.K. which uses pulses of electromagnetic energy to disrupt the electronic systems of modern cars, causing them to shut down and cut the engine. Here's a description of how it works: "At one end of a disused runway, E2V assembled a varied collection of second-hand cars and motorbikes in order to test the prototype against a range of vehicles. In demonstrations seen by the BBC a car drove towards the device at about 15mph (24km/h). As the vehicle entered the range of the RF Safe-stop, its dashboard warning lights and dials behaved erratically, the engine stopped and the car rolled gently to a halt. Digital audio and video recording devices in the vehicle were also affected.''It's a small radar transmitter,' said Andy Wood, product manager for the machine. 'The RF [radio frequency] is pulsed from the unit just as it would be in radar, it couples into the wiring in the car and that disrupts and confuses the electronics in the car causing the engine to stall.'"