Controversial proposals for an Aberdeen bypass could cost between £200m and £400m, it has been revealed.
The proposed bypass routes are costing more than expected
A series of possible route options have been outlined at the start of a consultation exercise.
Plans favoured by the city council would be cheapest at between £210m and £280m. But the proposals face a campaign of opposition.
Transport Minister Nicol Stephen said a decision would be taken once responses have been examined.
He argued that the new road would significantly reduce traffic congestion and boost the local economy.
Launching the consultation exercise Mr Stephen stressed that the Scottish Executive remained determined that the scheme should go ahead.
The local authority's blueprint, originally estimated at costing £120m, is facing opposition from the Camphill community for people with learning difficulties.
Their properties at Myrtle would end up on either side of the proposed new road.
The scheme was lambasted by environmentalists.
North East Green MSP Shiona Baird condemned the bypass plans
She said: "This project is yet another example of the executive's refusal to face up to the facts on climate change.
"This is a nonsensical project that will exacerbate the chaos and expense that increasing pollution will cause in terms of public health and climate change."
The MSP said ministers should be consulting on alternatives to the bypass instead of route options.
She said: "This incredibly short-sighted project highlights the executive's willingness to press ahead with projects that blatantly contradict their rhetoric on reducing pollution.
"This is a sad indictment on the coalition partners and extremely worrying for Scotland's contribution to the global effort on climate change."
The project could be driven through the Camphill development without destroying it, according to a Scottish Executive study published last month.
The probe suggested residents could even be moved during construction. The community has warned the road would ruin its special atmosphere.
The Camphill community is fighting the plans
The Camphill organisation was founded in Aberdeen almost 70 years ago and has grown into an international movement dedicated to helping adults and children with special needs.
There are more than 90 Camphill communities in 21 countries, including 47 in the UK and Ireland.
The Deeside community has become the focus of an international campaign. Protesters claim the proposed bypass would destroy it.
They fear also that constant traffic noise could disrupt work done at the Camphill Rudolph Steiner school with children suffering from severe behavioural problems
The executive had asked Professor James Hogg of Dundee University to investigate the human impact.