The State Highway 20 Mt Roskill Extension extends the Southwestern Motorway 4.5km from Queenstown Road in Hillsborough through Mt Roskill to Maioro Street in New Windsor. The motorway has two interchanges and incorporates provision for future bus shoulder lanes and rail.
The purpose of the State Highway 20 Mt Roskill Extension is to create a further key link in the Western Ring Route, providing a high standard, strategic extension of the highway from Queenstown Road through to Maioro Street.
This project was completed on 15 May 2009.
SH20 Mount Roskill Extension is a key part of the Western Ring Route. Once completed, the Western Ring Route will provide a genuine alternative to SH1 between Manukau City and Albany via SH20, SH16 and SH18.
The $186M State Highway 20 Mt Roskill Extension was completed on 15 May 2009. This four-lane, four kilometre motorway extension provides an alternative regional route through greater Auckland, linking the cities of Manukau, Auckland, Waitakere and North Shore.
The extension itself also provides considerable relief to local roads in the Mt Roskill and Avondale areas that previously carried through traffic from the Southwestern Motorway (SH20) to the CBD and Auckland’s western suburbs.
A ‘shotcrete’ method was used on the piers of the Dominion Road Bridge to create an artificial exposed surface showing the dark red colour and form of the original basalt rock found during construction. The surface was sprayed with concrete and then shaped by hand using templates from the existing rock surface, to create a natural looking face. This surface provides a visual reference to the natural volcanic characteristics of Mt Roskill, which is located directly behind the bridge.
