The Forrest Highway, Kwinana Freeway and Mitchell Freeway, are without a doubt one of the most important road systems in the Perth metropolitan area, and the southwestern part of the state.
Running in a north-south direction, the freeways link the north and southern suburbs of Perth together plus the southern city of Mandurah and the state's southwest, but also act as a coastal link between the northern and southern parts of the state. Built in stages from the late 1950s the route has seen enormous changes / extensions and is continuously undergoing expansion to this day.
Unique to the freeway sections is the passenger railway line down the median of the road corridor. This runs from The Spectacles to Perth, then from West Perth to Butler. The Mitchell Freeway at Nowergup features a railway stabling yard and depot in the median.
When first planned, the Mitchell Fwy was called the Yanchep Highway, as it is envisaged that eventually the route will connect to the town.
The section of State Route 2 south of Baldivis involved the design and construction of 70.5 kilometres of dual carriageway. The route was constructed as a single project and extended the dual carriageway from Safety Bay Road in Baldivis, around the eastern side of the Peel Inlet and Harvey Estuary to join the existing dual carriageway on Old Coast Road at Lake Clifton.
The route was constructed to freeway standard from Safety Bay Road to South Yunderup, a distance of 32 kilometres. The remainder of the route, 38 kilometres, was initially be built as a rural highway, with the ability to upgrade it in the future as traffic demands increase. The route links Perth and the South West, bypassing the heavily populated areas in Mandurah and the Dawesville Peninsula, and avoiding inland communities on the existing highway.
As part of the work, five interchanges were constructed at Safety Bay Road, Karnup Road, Paganoni Road, Lakes Road and Pinjarra Road. Nine intersections were constructed and have the capacity to be upgraded to interchanges in the future. They are located at Beacham Road, Greenlands Road, Paull Road, Mills Road, Herron Point Road, Old Bunbury Road, Dorsett Road, Old Coast Road and Peppermint Grove Road. In total, 19 bridges were built to grade separate the interchanges and extend the new Perth-Bunbury Highway over the Serpentine River, Nambeelup Brook, Murray River/Pinjarra Road, South Yunderup Road, Murray River floodplain, Harvey River and a number of Water Corporation drains. At the time, it was the largest infrastructure project ever undertaken by Main Roads Western Australia.
This page concentrates on the former alignment between Heathridge and Alkimos