UK-based E2V company is working on a system which can remotely shut down a car's engine.
The prototype device is called RF Safe-Stop created by E2V from UK and uses radio frequency pulses to "confuse" a car's electronic systems which will cut off the engine. The system can work at a range of up to 50 meters (164 feet) and uses L- and S-band radio frequencies to "safely" stop cars and motorcycles.
RF Safe-Stop's product manager Andy Wood is describing it as a “small radar transmitter” and that it could be effective against other types of vehicles as well, such as boats. Since it fiddles with electronics, the system isn't going to work on all older vehicles.
As you would imagine, the police have already expressed their interest in such a device.