Work to prepare the Bussell Highway dual carriageway between Busselton and Capel is expected to start in June after the start government allocated $4 million to align the area with fill.
The funds will be drawn from Main Roads minor works budget for forward works.
Due to land in the area being previously mined from mineral sands, sub-soil conditions were weak, and the compaction process would take about a year before road construction could safely proceed.
The state government is also proposing to roll the Bussell Highway duplication project into the wider Bunbury Outer Ring Road to save taxpayers money and allow works to start sooner rather than later.
However, widening the scope of the BORR project to include the Bussell Highway required agreement of the Commonwealth, and this would not happen during the election period.
The Bussell Highway duplication is planned to be delivered in two stages, with the $4 million to cover early works for the first section between the Capel bypass and Hutton Road.
Transport Minister Rita Saffioti said said the Bussell Highway duplication had been undergoing planning, land acquisition and environmental processes for quite some time, and they were now excited to be the first government to set the foundation for the upgrade to proceed.
"Locals and regular visitors to the South-West would be familiar with the dreaded bottleneck where the road narrows to one lane, which is badly exacerbated on long weekends," she said.
"Since coming to office, the McGowan Government has consistently publicly called for Commonwealth funding towards this important project following the previous Liberal-National government's failure to deliver the upgrade despite nearly nine years in office.
"We are now getting on with the job, and will be optimistically working with the next Federal Government to allow the project to rolled into the wider Bunbury Outer Ring Road project."
Vasse MLA Libby Mettam welcomed the announcement and said while it was only a small part of the $80 million in total needed to upgrade the 17 kilometre section of the highway, it was a step in the right direction.
"I welcome this announcement and see it as a win for the community that has campaigned so hard to make this notoriously dangerous section of the highway safer," Ms Mettam said.
"This is an issue that we have raised continually with the McGowan Government, both through a grievance to parliament last year, and two petitions calling for urging action.
"More than 6,000 people signed those petitions and it seems that finally the government is taking those concerns seriously."
There were 59 crashes on the highway between Busselton and Capel between January 2016 and December 2018, three of which were fatal.
This stretch of highway was also identified by the RAC as the riskiest road in WA and the number one priority for funding.
From March 2018 to March 2019, almost 13,000 vehicles travelled on the stretch of highway every day, with a peak 21,116 on March 1 this year.
"This project was identified as a priority by the former Liberal-led Government and site environmental surveys started in 2015," Ms Mettam said.
"It is disappointing it has taken so long for the McGowan Government to put politics aside and commit to continuing the work started by the previous government but I welcome today's first step."
City of Busselton mayor Grant Henley said a commitment to commence preparatory works on the first segment of this stretch of dangerous narrow highway was very welcome news.
Mr Henley said it was a clear indication that the WA Government recognised the community's safety and congestion concerns regarding this section of the highway.
