The Coalition has promised to get the ball rolling on duplicating the Augusta Highway, pledging $64 million towards double lanes from Port Wakefield to Port Augusta.
Such an upgrade to the 200-kilometre stretch of road has a price-tag of $1.2 billion according to the Civil Contractors Federation (SA) while the state's peak motoring body, the RAA, has estimated it could cost up to $2 billion.
Deputy Prime Minister and Minister for Infrastructure, Transport and Regional Development Michael McCormack said the additional funding would improve safety and address pinch points along one of the nation's greatest road assets, the Princes Highway of which the Augusta Highway is just a part.
"The Princes Highway is a major freight and passenger route along the east coast of Australia, extending from New South Wales through Victoria and terminates in Port Augusta," he said.
"We are proud to be investing in this nationally significant corridor in order to support local communities, tourism and industries that rely on this road every day."
Federal Member for Grey Rowan Ramsey said he has been campaigning for this outcome for some time.
"Traffic loads to the north and west through to WA are increasing every year," he said.
"We have added more passing lanes and certainly that has made a difference, but the case for dual lanes all the way to Port Augusta keeps increasing."
Mr Ramsey said the $90m dual lane and fly-over solution for Port Wakefield and the $200m duplication of the Joy Baluch Bridge, both 80 percent funded by the federal government have provided the book-ends, now they could set about filling in the gap.
"Safer and faster, the dual lane project delivers the infrastructure we need to enable northern SA to reach its full potential," he said.
"It will also significantly increase safety."
The South Australian Labor Party was quick to pour cold water over the announcement, saying $64 million was just a small portion of what the project would actually cost.
South Australia's Shadow Minister for Transport and Infrastructure, Tom Koutsantonis, described the announcement as a sham.
"We know the experts predict this project would cost $1.2 billion - yet the Liberals have only offered $64 million," he said.
"Where is the remaining $1.1 billion coming from?
"People in the Iron Triangle know $64 million is a drop in the ocean compared to the actual cost of duplicating this road."
Leading up the federal election, the RAA called on the next federal government to make upgrading the highway a priority.
RAA's senior manager of road safety, Charles Mountain, said such a project was a high priority given the traffic - including B-doubles and freight vehicles - that use the road as well as anticipated growth and developments in the Upper Spencer Gulf area.
"The importance of the corridor will increase," he said.