The state and federal governments will spend $366 million to remove two major traffic light congestion points on Tonkin Highway.
The government is looking for contractors to build elevated interchanges at Hale Road and Welshpool Road with construction expected to begin by the end of next year.
The highway will also be widened to a six-lane dual carriageway between Roe Highway and north of Kelvin Road and a bike path installed along the eastern side of the road.
The upgrade will address the abrupt end at Hale Road to the series of free-flowing interchanges on Tonkin Highway built over the past decade as part of the Gateway WA, Tonkin Gap, and North Link projects.
More than 50,000 vehicles use this section of Tonkin Highway daily, 13 per cent of which are heavy vehicles.
The state said the economic costs of congestion on Tonkin Highway was predicted to be the fifth worst across the state by 2031.
The federal government will pay $293 million toward the project while the state will spend $73 million.
WA Transport Minister Rita Saffioti said this stretch of Tonkin Highway was a notorious bottleneck, particularly the Welshpool Road intersection which regularly rates as one of the worst for congestion.
“This project will complement the Tonkin Gap Project, which recently reached completion, and is providing commuters with faster travel times and a safer journey,” she said.
“This important upgrade project will improve safety and the movement of freight and people by creating free-flowing traffic conditions.”
Federal Infrastructure, Transport, Regional Development and Local Government Minister Catherine King said the project would also create thousands of jobs.
The Tonkin Highway between Hale Road and Kelvin Road is a major bottleneck.Credit: Jason South
The government was also planning for an interchange upgrade at Kelvin Road which would occur after environmental approvals were granted.
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