Stopping the controversial Norwich Western Link will be their priority at County Hall, say newly-elected Green county councillors.
Norfolk County Council has its first Green councillors since 2017, after taking seats from Labour in Friday's election counts.
Jamie Osborn took Mancroft, Ben Price won in Thorpe Hamlet and Paul Neale triumphed in Nelson.
And Mr Osborn said their number one priority was to put pressure on the council to scrap the mooted £153m Western Link road.
in 2016, that road was made one of the Conservative-controlled council's priorities and the council's cabinet agreed a preferred route from the A1067 travelling between Weston Longville and Ringland.
But Norfolk Wildlife Trust and the Norfolk Rivers Trust have expressed concerns about the wildlife impact of the 3.9 mile road.
Independent bat experts Wild Wings Ecology, say the road would wipe out what they say is the largest barbastelle bat colony in the UK and Springwatch presenter Chris Packham recently urged rejection.
And Mr Osborn said the new Greens at County Hall would fight to prevent it.
He said: "The figures just do not stack up, in terms of the environment and in terms of money.
"Legislation has come in emissions need to be cut to zero by 2050 and to be down by 78pc by 2035.
"But the Western Link would push carbon emissions up by about 20pc."
The Labour group at County Hall is opposed to the road, while Lib Dem Steffan Aquarone quit as group leader over his party's support for it.
Mr Osborn said: "I am really pleased to see there is increasing opposition within the other political groups.
"The Greens have been campaigning about this for a long time and we will be happy to work with other parties to put the pressure on."
The Department for Transport gave conditional support last summer.
The council must submit a business case to the government, but that has been delayed three times.
Supporters include the Norfolk and Norwich University Hospital, Norfolk Chamber of Commerce, Norwich Airport, First buses and Konectbuses.
Council leaders say it would bring economic benefits and ease rat-running and they would mitigate for any environmental impact.
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