Money saved from four key road projects will be used to pay for a Liberal Party plan to widen a 17km gridlock-prone stretch of the Mitchell Freeway.

Colin Barnett will today commit a re-elected Liberal Government to building extra southbound lanes between Hodges Drive and Vincent Street to improve morning peak traffic flow.

It will cost $114 million, with work scheduled to begin in April and finish late in 2019.

“People travelling towards the city in morning peak hour know that the Mitchell Freeway is particularly congested due to bottlenecks created from traffic lanes being forced to merge at three places along the freeway,” the Premier said yesterday.

“When finished, the additional lanes will greatly reduce congestion during this peak period, generating improved travel times for road users.”

The project, which Mr Barnett said would create up to 455 jobs, would create three continuous traffic lanes from Hodges Drive to Reid Highway and four continuous lanes from Reid Highway to Vincent Street.

State Budget updated figures released yesterday showed the $114 million has been re-allocated from savings made on four jointly funded Commonwealth/State road projects.

They are:

NorthLink WA ($76.3 million).

Upgrading the Minilya to Barradale stretch of the North West Coastal Highway ($18.3 million).

Work on the Walgoolan to Coolgardie section of Great Eastern Highway ($13.6 million).

The Roe Highway to Russell Road stretch of the Kwinana Freeway ($5.8 million).

Transport Minister Bill Marmion said the project would have an enormous impact on families living in the northern suburbs.

“The Mitchell Freeway caters for some of the highest traffic demands in Perth, with up to 190,000 vehicles per day,” Mr Marmion said.

A supporting technical document attached to the Barnett Government’s long-term transport plan — which was finalised and released last week — said the widening of the Mitchell Freeway up to Ocean Reef Road was constrained by “overpass, underpass and pedestrian structures”.

It said this could necessitate removing emergency lanes and reducing inside and outside shoulder widths.

It also said it could necessitate introducing “managed freeways” — where traffic lights are used to control freeway on-ramps.

Mr Marmion said the extra lanes on the Mitchell Freeway would complement other recent congestion-busting projects, including the $8.5 million roll-out of new merge lines on Perth’s freeways and highways and the recently completed $14 million intersection upgrade at Graham Farmer Freeway and East Parade.