Proper enforcement of the 70mph road speed limit would offer a "quick win" in the battle to reduce carbon emissions from road transport, research out today showed.

Keeping driving speeds below the limit would cut emissions by around 1m tonnes a year by 2010, according to the UK Energy Research Centre (UKERC) - twice as much as the government has claimed could be cut by this kind of initiative.

The centre said that a lowering of the speed limit to 60mph would cut carbon emissions by nearly 2m tonnes a year or 29% of the total savings expected from the transport sector by 2010.

The estimates were contained in a report by the UKERC which added that strict enforcement of the 70mph speed limit would be cost-effective and potentially popular.

The centre said the use of variable speed limits as low as 40mph on the M25 around London and on the M42 in the Midlands had the support of more than two thirds of drivers using them.

Dr Jillian Anable of the Centre for Transport Policy at Robert Gordon university in Aberdeen, one of the report's authors, said: "Enforcing the upper speed limit would produce clear environmental benefits, and help to raise awareness of the reality of climate change and of the need for everyone to take action on it.

"Through measures such as this, the gap between the original emissions target for 2010 and what is currently predicted could be closed."

In June, the transport secretary, Douglas Alexander, told the House of Commons' environmental audit committee that the introduction of lower speed limits had not been included in the government's climate change programme for fear of "popular antagonism".

A spokesman for the AA Motoring Trust agreed that drivers would want to see new rules to cut limits to reduce emissions, but that they could be persuaded to drive more slowly by other means.

"Drivers might drive more efficiently if you tell them about the money saving there is to be had," he said.

Cutting their driving speed from 80mph to 70mph could save drivers 40p for every 10 miles that they drive, he said, and increasing awareness of these kinds of cost benefits could encourage slower driving.

"There's no reason why the Highways Agency shouldn't use its message boards [on motorways] to stimulate more economic driving," he added.