A national road-pricing system should be introduced to make motorists pay for reducing carbon dioxide emissions, according to the government’s climate change advisory body.
In addition, the board has said that the speed limit on all motorways should be more strictly enforced and may have to be reduced to 60mph to help to meet legally binding carbon reduction targets.
The Committee on Climate Change, which devised the CO2 reduction targets and advises the government on how to meet them, has reported that emissions aren't dropping fast enough.
Among its suggestions for meeting targets are the introduction of road pricing as an additional tax on motorists, alongside fuel tax.
The report says: "From an emissions perspective, road pricing should be introduced as a complement to fuel duty rather than a substitute. This conclusion is buttressed by the fact that fuel duty plays a crucial role in providing incentives for purchase of electric cars, increasing electric car cost savings relative to conventional cars.”
It says that by 2020, road pricing could save 5.6 million tonnes of carbon dioxide a year — 5 per cent of total road transport emissions. It says the savings could rise to 15 per cent a year by 2040.
The report concludes: "Road pricing could be a useful component of a strategy for transport emissions reduction, and the committee recommends that this should be seriously considered by the government."
It also calculates that rigorously enforcing the 70mph limit would save 1.4 million tonnes of CO2 a year.
It says that reducing the motorway limit to 60mph would save an additional 1.5 million tonnes of CO2 a year.
It also says the government may have to double the grants planned for electric cars from 2011 to £10,000 for at least the first 25,000 buyers. It says otherwise the extra cost of battery-powered cars would be prohibitive.
The committee concludes that the total subsidy needed to achieve widespread use of electric cars is likely to be £800 million, rather than the £250 million pledged by ministers.