A recent proposal to limit the speed cars can reach is proving controversial. The idea, put 1 by the Institute for Road Safety, involves fitting vehicles with a communications box containing a digital map of the road network. While a car is in motion, the communications box — which knows 2 fast the vehicle is legally permitted to travel on a particular section of road — automatically regulates the car’s speed. It, therefore, becomes impossible for a vehicle fitted with 3 a device to exceed the speed limit. There are plans to charge motorists to drive into the centre of major cities, and a communications box could be used to identify vehicles that enter this zone. At present, 4 time a vehicle does so, its number plate is photographed. Then the number is compared against a list of authorised vehicles, but this system is costly and 5 from foolproof. The system could be put in place quickly if the government wished as part 6 the technology has already been developed for another purpose. Electronic vehicle identification is unpopular with some people, who regard it as an infringement of their rights. 7 would certainly object to the plan to restrict the speed of their cars, which may make the government hesitate to go through with it. But by forcing drivers to slow 8, the scheme would save lives, and this is likely to be popular with the general public.