Galloway and West Dumfries MSP Finlay Carson has been assured the Scottish Government will take full account of the report being prepared by local authorities in south Scotland, including Dumfries and Galloway, South Ayrshire and East Ayrshire, along with Mid and East Antrim Borough Council in Northern Ireland.
There had been fears that the information contained in the impact assessment would be ignored if it was not available before the end of the public consultation period that closes on April 15.
However, Mr Finlay has been now been given an assurance from the Scottish Transport Minister Jenny Gilruth that it will still be considered even after the deadline passes.
He said: “I believe that the EIA being undertaken will be hugely important in identifying how critical the two routes are, not only to the south west of Scotland and Northern Ireland, but to the whole of the UK.
“I am delighted the Scottish Transport Minister has confirmed to me in a letter that the economic impact assessment will be given careful consideration.
“My fear was that it would miss the deadline and that is why I originally asked for an extension.
“Especially as the information contained in the report will be crucial in strengthening the argument for immediate investment in both roads.”
Mr Carson had originally sought for an extension to the consultation process regarding key transport projects across Scotland, but this was ruled out due to the upcoming council elections.
In her response, Ms Gilruth said that STPR 2 recommends that safety, resilience and reliability improvements on the A75 and A77 strategic road corridors, in turn supporting placemaking opportunities.
She added: “This would include, but not limited to enhancing overtaking opportunities, widening or realigning carriageways and improving junctions.
“These would provide more resilient connects to the draft NPF4 national developments at Stranraer Gateway, Chapelcross Power Station Redevelopment and the ports at Cairnryan.”