The package includes a major programme of motorway and trunk road widening, and stepping up traffic management measures, including hard shoulder running at peak periods where it can be done safely. The package will add significant capacity to Britain's strategic road network and improve safety as well as tackling the worst congestion hotspots, he said today.

But he rejected a number of proposed schemes across the country, which were felt to have unacceptable and avoidable consequences to the local environment, calling instead on local planners to find less damaging alternatives.

Mr Darling also underlined the need to plan to manage demand for road travel in the future, by publishing a Discussion Paper - "Managing our Roads". As part of this, he launched a feasibility study to look at the practicalities of road pricing for cars in future decades.

Alistair Darling said:

"This new investment in our major transport corridors will deliver real improvements for people and businesses across the country.

"The improvements are essential to tackling congestion on major routes - particularly the widening of the M25 and M1. They will add vital capacity to the strategic road network and support economic growth.

"But unless there is an overriding public interest, there should be a strong presumption against building roads through areas of outstanding natural beauty or other sensitive sites.

"Looking ahead 20 to 30 years as the economy grows and people become better off, we face increasing pressure on road space. We will not be able to build our way out of all the pressures we will face.

"Road user charging has to be considered as part of sensible management of our roads. It could provide a far better deal for motorists giving them choice as to how and when they travel. So today I have ordered a feasibility study to look at the practicalities of such a scheme. There are many issues that need to be addressed such as protection of privacy and whether any scheme could work technically. We would be failing future generations if we did not find out if this is feasible and examine what gains could come from it."

Today's improvements will:

Upgrade national transport corridors

• Plans to widen most of the remaining three lane sections of the M25 to four lanes with £1.7bn investment over the next decade.
• Plans to widen the M1 between the M25 and Milton Keynes to dual four lanes, costing £623 million
• Plans to widen the M11 between junctions 8 and 9 - £171 million.
• Capacity improvements to the M1, M18, M62 and the A1/A1(M) in South and West Yorkshire - £1.2 billion.
• Improvements to the M60 around the north and West Manchester - £479 million
• Accept case for a new motorway link between the M6 Toll road and the M54 - £55 million.
• Dunstable Northern Bypass linking the A5 to M1 - £48m
• Dualling 8 miles of the A421 between the M1 and Bedford -£171m
• Major improvements to the A19 at the Seaton Burn and Testos junctions - £140 million.
• A £246 million package of improvements to the A12 corridor, including the upgrade of the A12 to dual three lanes between the M25 and Chelmsford.
• Dualling the A120 between Braintree and Marks Tey - £203 million

• The proposed bypasses of Stourbridge and Wolverhampton in the West Midlands have been rejected on environmental grounds. There will be a further examination of the needs of the Black Country.
• Schemes on the A27 along the South Coast at Arundel, Chichester, Worthing, Selmeston and Wilmington have been rejected on environmental grounds.

Improvements to local transport and rail

• Up to £1bn for the West Midlands conurbation to work up a package of major public transport and road improvements, potentially including light rail and bus schemes.
• Local authorities in the Thames Valley and other areas encouraged developing proposals for long distance coach and bus services, park and riding sites and transport interchanges.
• - SRA to consider scope for delivering service enhancements across the areas covered by the MMS through its Route Utilisation Strategies and other on-going development work.