Politicians are stepping up the pressure for a full upgrade of the A90 north of Ellon.
North East Conservative MSP Nanette Milne called on the Scottish Government to back a specific study into the dualling of the busy route to Peterhead.
But transport minister Derek Mackay said in an answer to her Parliamentary question last week there were no plans for a dual carriageway.
Work is getting under way in full this month on the Aberdeen by-pass and Balmedie-Tipperty dual carriageway projects.
However, demands are intensifying for dualling between Ellon and Peterhead.
Mrs Milne has strongly criticised SNP ministers for failing to support a major upgrade of the route.
She said: “It is hugely disappointing at the lack of commitment by the Scottish Government to fully upgrade the A90, a road that is rapidly becoming one of Scotland’s most notorious.
“Northern Aberdeenshire has seen significant growth in population and the development of the Energetica Corridor is vital to the future economic growth and regeneration of that area.
“The A90 between Ellon and Peterhead is now perhaps the last key strategic trunk road in Scotland needing upgrading.
“The North-east is at the heart of the Scottish economy and we need investment in our transport infrastructure.”
Meanwhile, Ellon and District Councillor Gillian Owen, who is spearheading the “Why Stop at Ellon” campaign, has invited Mr Mackay to visit the town to discuss the A90 issue.
In a reply to a recent letter from the minister, she says: “The need for dualling through to Peterhead remains the same as for the Balmedie to Tipperty route.
“The existing single carriageway section is not capable of providing efficient access to and from the north of Aberdeen, particularly at peak periods.
“The problem has increased year on year since 2005. This affects all users including cars, freight and bus services exacerbated by platoons of traffic regularly forming along the section behind slow-moving vehicles.”
A Scottish Government spokesman said: “We recognise that the A90 is an important route for businesses along the North-east coast, particularly the Energetica Corridor.
“Nestrans are currently undertaking an appraisal which will consider the strategic transport connections on the A90 from Fraserburgh and Peterhead to Aberdeen and we have committed £25,000 towards the costs.
“A consultant team has been appointed by Nestrans, and Transport Scotland who have been part of inception discussions which started in recent weeks, will continue to work with the client group as work progresses.
“Quite rightly our current focus is on ensuring the existing major projects currently underway are delivered bringing benefits to the people of the North-east.”