The Kwinana Freeway extension and Forrest Highway was a dynamic and challenging infrastructure project, involving the design and construction of 70.5 kilometres of dual carriageway from Safety Bay Road in Baldivis to Old Coast Road in Lake Clifton.
The Kwinana Freeway extension comprises 32 kilometres of freeway standard road from Safety Bay Road in Baldivis to South Yunderup Road, South Yunderup. The remainder of the route, the Forrest Highway, is a rural highway with the ability to be upgraded in the future as traffic demands increase. The entire route is continuous dual carriageway, with two lanes in either direction.
Funded by both the Commonwealth and State Government of Western Australia, the project doubled the length of the existing freeway network and now provides a high standard inter-regional road link, improving transport connectivity and road safety.
The route connects Perth with the South West, bypassing the heavily populated areas in Mandurah and avoiding inland communities on the existing highway. The result – reducing travel time for road users by around 30 minutes.
Six interchanges provide access to the Kwinana Freeway extension at Safety Bay Road, Karnup Road, Paganoni Road, Lymon Road, Lakes Road and Pinjarra Road.
Ten intersections provide access to the Forrest Highway and they are located at Beacham Road, Greenlands Road, Paull Road, Mills Road, Birchmont, Herron Point Road, Old Bunbury Road, Dorsett Road, Old Coast Road and Peppermint Grove Road.
In total, 19 bridges were constructed to grade separate the interchanges and extend the Kwinana Freeway extension over the Serpentine River, Nambeelup Brook, Murray River/Pinjarra Road, and the Forrest Highway over South Yunderup Road, Harvey River and the Mayfield Drain.