Technology puts brakes on speeders

Speeding motorists could be slowed down by on-board computers which would automatically override the driver and apply the brakes. Trials could begin next year on the M4 motorway between London and South Wales.

Roadside beacons would send radio signals to the computers of passing cars, telling them the speed limit. If the driver is speeding, the computer would apply the brakes gently but firmly. The motorist would also find that if he or she tried to exceed the speed limit, the accelerator would refuse to work.

Tests on drivers in simulators suggest that the loss of control does not anger them, according to the Institute for Transport Studies at the University of Leeds, which carried out the trials.

Another option is for each car to carry a digital map containing information on speed limits. Data on traffic jams, poor weather conditions and even crowding from people leaving a football match could be transmitted to each car and the speed limit reduced to suit the circumstances.