Supreme Court judges in London have ruled that the proposed Aberdeen bypass, which will pass through Lower Deeside, can go ahead.
Campaigner group RoadSense has been fighting to stop the £400m route which would join the A90 from Blackdog to Stonehaven.
The near 30-mile planned road - known as the Aberdeen Western Peripheral Route (AWPR) - was given approval by Scottish ministers in 2009 following a public consultation which RoadSense claimed was flawed.
Two appeals against the final route by the group have already been thrown out by judges in Scotland. Politicians have welcomed the courts decision.
Aberdeenshire Council welcomed yesterday’s decision from the UK Supreme Court.
Leader Jim Gifford said: “It’s the decision that we’ve all been waiting for and I’m delighted that after a decade of planning, enquiries and legal proceedings, we finally have the green light to move ahead with this project.
“The majority of residents and businesses in the North East of Scotland have been waiting for progress on the Aberdeen Western Peripheral Route for far too long. Today marks the beginning of the delivery of the most significant piece of major infrastructure in the North-east of Scotland, since the discovery of oil in the North Sea in the 1960s.
“I’m delighted that at last we can get on with this project which is seen very much as the key to unlocking the full potential of Aberdeenshire, particularly the Energetica corridor up to Peterhead.
“Of course, the road won’t be built next week. We now move into a phase of land purchasing and procurement, but at last we can set realistic timescales, develop project plans and move forwards with identifying funding streams for this work.
“Aberdeenshire Council is committed to working with Aberdeen City Council and Transport Scotland to see the Aberdeen Western Peripheral Route become reality as quickly as possible.”
North-east Liberal Democrat MSP Alison McInnes is hoping work gets under way as soon as possible.
She said: “The Scottish Government must now act quickly to drive this project forward. It has had months to finalise its plans while awaiting this latest appeal. It needs to finally provide a concrete timetable, details of the construction costs and explain how it will fund the project. It can no longer blame legal gridlock for its inaction.”