Campaign group RoadSense has lodged an appeal after Lord Tyre rejected its judicial review case on the Aberdeen Western Peripheral Route (AWPR) last month.
The proposed 28-mile road, which would create an alternative route from north to south Aberdeen, bypassing the city, was given the go-ahead in 2009 by the Scottish government following a lengthy public inquiry.
But the project has been delayed by legal objections and now faces a further setback with this latest appeal.
Lord Tyre concluded that there had been sufficient consultation on the route, that the restricted remit of the public inquiry had not been unreasonable and ministers had done enough to meet European legislation requirements on habitats and species.
But RoadSense chairman William Walton said: "RoadSense’s position continues to be that the procedure for selecting the AWPR route, including the addition of a new Fast Link to Stonehaven, was flawed and that the public were denied the opportunity for proper consultation.
"RoadSense continues to maintain that there has been a breach of European directives with respect to protected habitats and species."
The group says if it were convinced that this route was the best solution to the area’s traffic problems then it would not be continuing to fight.
Transport minister Keith Brown expressed frustration over the appeal. He claimed that 11,000 people have signed a petition urging the objectors to accept the decision of Lord Tyre.
"Despite the continued actions of this tiny minority, the Scottish government remains totally committed to the AWPR being completed as soon as possible", he said.
"As with the initial legal challenges we will robustly defend the appeal submitted to the Inner House of the Court of Session."