A £42m bypass in north Devon has received final approval after the Appeal Court dismissed objections by environmental campaigners.
The proposed bridge will be 409m long
The new road will reduce traffic in Barnstaple town centre and cut journey times for motorists on the A361.
About £38m of the total amount needed for the scheme will be coming from the government. Devon County Council will also contribute to the scheme.
Construction work is due to begin in spring next year.
Plans for the Barnstaple western bypass include a 2.7km (1.7 mile) stretch of new road and a 409m (447 yard) long bridge across the River Taw, to be known as the Downstream Bridge.
The proposals were put forward by Devon County Council to try to alleviate traffic congestion in the town.
Environmentalists argued the bridge would attract more vehicles into the area and clog up the roads even more.
Friends of the Earth campaigners battled to stop the project by making a legal challenge at the Appeal Court last summer.
They said the scheme would disturb large numbers of seabirds on the Taw and Torridge Estuary, along with the habitat of endangered otters. But the appeal was dismissed by three Appeal Court judges.
Transport Minister Charlotte Atkins announced that the government had fully accepted the scheme for construction.
She said: "The government is committed to improving the road network, securing quicker and more reliable journey times whilst reducing the impact on local communities."
Devon County Council had applied to the government for additional funding, because legal challenges and delays had increased the cost of the project.
Barnstaple County Councillor Brian Greenslade said he was delighted with the news and that the bypass would bring "enormous economic and environmental benefits" to the area.