A new report has called on the Government to use cameras to ensure that drivers stick to the 70 mph speed limit on motorways, which would lower carbon emissions and cut road accidents claims the report.

Figures from the Department of Transport show that the speed limit is ignored by more than half of all motorists and the Sustainable Development Commission says that new average speed cameras could be an effective tool in trying to get motorists to comply.

The new cameras would measure a car’s speed over a prolonged distance and avoid the current problem with fixed cameras whereby drivers brake when seeing them and accelerate off after passing them.

The Commission says that encouraging more people to stick to the speed limit would lead to more environmentally friendly driving, reducing the level of carbon dioxide by up to 1.4 million tonnes.

Average speed cameras are normally used at road works but 10 permanent sets have been introduced onto the country’s motorways following their success in reducing the number of road accidents and speeding fines.

The Commission has also called for all cars to be fitted with speed limiters to cut carbon emissions and it has urged the Government to set a timetable to introduce new technology which would make it impossible for cars to break the speed limit, though it accepts that this could take many years to achieve.