Motorists face more major disruptions from tomorrow as construction of the $1 billion Gateway WA - the State's biggest and most expensive road project - marches towards a new mid-2016 completion date.
Work on the pivotal Tonkin Highway-Horrie Miller Drive intersection will require major diversions around the site that will almost certainly lead to traffic delays for several months.
Northbound traffic on Tonkin Highway will be unable to turn right into Horrie Miller Drive and traffic on Kewdale Road will be unable to turn left on to Tonkin Highway.
Southbound traffic on Tonkin Highway looking to turn left into Horrie Miller Drive will need to deviate about 500m before the intersection and travel on a new ramp.
Transport Minister Dean Nalder conceded yesterday the project was causing disruptions but he believed most motorists were understanding and appreciated the significance of the work.
"The transformed road network will have a huge impact on alleviating congestion for road users," Mr Nalder said.
"As the second half of the project advances, positive effects will be felt across the city as major elements of the upgrade are progressively opened to traffic.
"The improvements within the Kewdale industrial precinct are almost finished and four of the five new interchanges will come on stream before the end of the year."
The Gateway WA project began late in 2013 and is jointly funded by the Federal ($676 million) and State ($310 million) governments.
It involves the construction and upgrade of five main interchanges, the widening of Tonkin Highway to six lanes between Great Eastern Highway and Roe Highway and the upgrading of Leach Highway between Tonkin Highway and Orrong Road to an expressway.
Its centrepiece is the three-level interchange at Tonkin Highway and Leach Highway, the main gateway from Perth International Airport into the city. It will be 13.9m from its lowest to highest point.
Mr Nalder said the project was six months ahead of schedule, largely because of favourable weather.
It is also $45 million under budget, money that has been transferred to the upgrade of the accident-prone Roe Highway-Berkshire Road intersection in Forrestfield.
Mr Nalder joined Federal Assistant Infrastructure Minister Jamie Briggs yesterday to inspect the new tunnel that will form the basis of the Leach Highway-Abernethy Road intersection - one of the new interchanges expected to be finished late this year.
Mr Briggs said Gateway WA was a "game-changing" project that supported 1300 construction jobs.
With the Swan Valley bypass road, Gateway WA will form part of the Perth freight link, the connection between Muchea and Fremantle port on which trucks will be charged a toll but not private cars.
'The transformed road network will have a huge impact on alleviating congestion.'"
- Dean Nalder * Transport Minister