The Department for Transport (DFT) is facing a potential High Court battle after it approved the redevelopment of the A47 between Blofield to North Burlingham.
Lawyers acting on behalf of Dr Andrew Boswell, a former Green county and city councillor, launched a legal challenge to the scheme last week.
Dr Boswell argues the government has failed to lawfully assess the impact of carbon emissions that would result from the scheme, reports the Eastern Daily Press.
But National Highways said it is working to lower emissions and that the dualled road will be a safer for the community.
The £90m scheme, which would see 1.6 miles of road dualled, was approved by government transport minister Grant Shapps in June.
Dr Boswell said: “In making his decision, Grant Shapps failed to properly follow environmental regulations for assessing carbon emissions from this A47 scheme with those from other large roads planned for the Norwich area.”
He also argued the scheme would destroy unspoilt countryside while severing footpaths connecting Lingwood and Burlingham – two villages east of Norwich.
He said: “Pedestrian access to schools, the [Lingwood] train station, buses, village hall, a recreation ground, and a post office would be lost as it will be impossible to cross a dual carriageway with 70mph traffic.”
If the court accepts the case it could see judges review the government’s approval, which Dr Boswell said could have national implications if his argument is accepted.
Dr Boswell has hired specialist environmental lawyers, Richard Buxton Solicitors of Cambridge, with funding coming from a crowdfunding campaign.
The department said it could not comment on ongoing legal proceedings, but has pledged to achieve net zero emissions and cut carbon from road building and maintenance.