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WestConnex M4-M8 Link Tunnels Project

2024 National Infrastructure Awards Finalist

WestConnex M4-M8 Link Tunnels Project


WestConnex M4-M8 Link Tunnels Project

The WestConnex M4-M8 Link Tunnels project delivered new twin tunnels which link the existing M4 motorway at Haberfield to the M8 motorway at St Peters. The $3.2 billion project involved the construction of 7.5 kilometres of tunnel at an average depth of 35 metres. By connecting M4 and M8, the link tunnel is expected to remove 4,000 trucks from Parramatta Road per day and up to 100,000 vehicles per day from surface road networks, and allows for the circumvention of 52 sets of traffic lights from Parramatta to Mascot. 

The Judging Panel noted the WestConnex M4-M8 Link Tunnels project achieved its objectives punctually and within budget, particularly noting the successful integration of the new contracting Joint Venture into the WestConnex programme. The Panel noted the early involvement of the mechanical and electrical teams and implementation of a “tunnel production line” approach, prevented bottlenecks and enabled all crews to work optimally. The Judging Panel also noted that the project achieved a 42% reduction in Scope One and Two emissions during construction, and a 63% reduction over the design life.