WORKS to widen the northbound section of the Mitchell Freeway between Hepburn Avenue and Hodges Drive will begin in September.
The $30 million upgrade, which will see the section of freeway widened from two to three lanes, was announced in May last year.
Transport Minister Troy Buswell said there would be some disruption for motorists when construction started, until its expected completion in mid-2013.
But he said that most of the work would be done at non-peak times.
“Freeway traffic volumes between Hepburn Avenue and Ocean Reef Road have grown rapidly in recent years, with daily volumes already approaching the 2016 forecast of more than 40,000 vehicles per day,” he said.
“The expansion from two to three lanes on this 7.2km section will increase capacity and help ease the congestion faced as people travel home from work each day.”
Mr Buswell also announced $57 million worth of upgrades to improve east-west traffic flow to minimise the disruption caused by the waterfront and city link developments last week.
“This Government is overseeing the most significant transformation of the CBD in decades and it is inevitable that key redevelopment projects such as the Perth Waterfront, Perth City Link and Riverside will change the way traffic moves in the city,” he said.
Work to widen the Northbridge tunnel to three lanes in both directions will begin in July and is expected to be completed in May next year.
July will also mark the start of works to add an extra northbound lane along the Graham Farmer and Mitchell freeways from the Northbridge tunnel to Hutton Street.
This work is expected to be completed in November 2013.