The A75 – which runs between Gretna and Stranraer – carries thousands of HGVs every year between the UK and Northern Ireland.
However official figures reveal it has one of the poorest safety records, with emergency services having been forced to close it on no less than 34 occasions in the last four years.
The most serious recent accident happened in January 18 when an HGV milk tanker and a car were involved in a collision at Barlae leading the road to be closed by police for more than 14 hours.
According to Transport Scotland figures obtained from SPICe – the information centre – the road was totally closed in both directions on 17 occasions.
Galloway and West Dumfries MSP Finlay Carson described the situation as “scandalous”.
He said: “Successive Scottish Government have promised investment to upgrade the A75 but have repeatedly failed to deliver on them.
“Not only is the road crucial to the local economy but also the national one yet transport ministers have struggled to recognise that.
“Crucially we are also talking about many lives being put at serious risk on a daily basis because drivers become impatient by being held up by lorries heading to the ferry port at Cairnryan.
“They inevitably become impatient and take chances often resulting in nasty crashes or vehicles veering off the road.
“Like most of the local communities along the A75 I have been campaigning for it to be turned into a dual carriageway in order to save lives but our calls are being totally ignored by the Scottish Government.
“Perhaps when they see this catalogue of incidents and the actual number of times the road has been closed they may have a change of heart. However I seriously doubt it.”
Mr Carson has already provided a submission to the Union Connectivity Review presently being undertaken by Sir Peter Hendy.
He said: “Hopefully he will recognise the important role the A75 plays because clearly the Scottish Government has no interest and didn’t even allow Transport Scotland officials to be involved.”