The Telegraph | December 30, 2008
By Jon Swaine

A panel from the Commission for Integrated Transport and the Motorists' Forum, both of which advise the Government on transport, say the technology would cut injuries from road accidents by 29 per cent and reduce carbon emissions.

The system would require detailed digital maps of Britain's roads, containing every speed limit, to be drawn up.

A device in vehicles would use satellite positioning technology to discover the limit in its location and reduce its speed if necessary.

The groups say the devices should be fitted on a voluntary basis and should contain a manual override feature, meaning drivers could break the speed limit if, for example, they were forced to overtake.

The report follows lengthy trials backed the Department for Transport, which has been in talks with the motor industry over how the devices could be made available.

John Lewis, who chaired the panel, said: "You can override the device that we're talking about, either by pressing a button on the steering wheel or by kicking down the accelerator as you would on an automatic car.

"But we conducted trials with 20 cars and 80 different drivers over an extended period, and actually the drivers found they changed their habits and changed their behaviour and might not have taken the risk of overtaking," he told BBC Radio 4's Today Programme.

However, critics have warned that a similar, existing system for truck drivers showed that the devices could cause drivers to not give driving their full attention.

Claire Armstrong, from the road safety charity Safe Speed, said: "They drive along at 56, they stick their foot on the floor because they know the equipment will not go any faster, and they pretty much go into fatigue mode, or zombie mode.

"They stop paying attention to the road, and that makes it highly dangerous in those scenarios. You've taken the responsibility away from the driver and that is not good for road safety."