Plans to build a relief road through protected countryside in Dorset before the 2012 Olympics have been approved by a High Court judge.
The relief road is set to relieve congestion on the A354 and A353
Environmental pressure groups lost their legal challenge to stop the controversial route through an Area of Outstanding Natural Beauty (AONB).
The new road to Weymouth and Portland is expected to be complete before the area hosts the Olympic sailing events.
Thousands of spectators and competitors are expected to descend on the towns.
The High Court judge in London refused permission for a judicial review of Dorset County Council's decision to grant itself permission for the £84.5m project drawn up to relieve congestion on the A354 and the A353.
Campaigners, including Campaign to Protect Rural England (CPRE) and Transport 2000, said the route will cut through the legally protected countryside and affect the ancient woodland and a nature reserve.
The court action to save a landscape which is part of "Hardy's Wessex" was backed by the Woodland Trust, Friends of the Earth and the Ramblers Trust.
But Dorset Council has the support of many local residents and businesses who say their daily lives and commercial activities are blighted by traffic congestion on the main road into the seaside town.
Campaigners said the road will cut through ancient woodland
Mr Justice Collins said the council's planning committee had sufficient grounds for deciding that the road scheme would foster the social or economic wellbeing of the communities in the area while still being compatible with AONB purposes.
He added that it was doubtful whether the pending Olympics had any relevance to the issue - irrespective of whether the people of Weymouth would welcome the games or dread the prospect of being "descended upon".
Work on the road scheme is due to start early next year.
The government has decided not to call a public inquiry into the scheme, despite the criticisms by campaigners.