Problem to be addressed
The Sydney Harbour Bridge and Sydney Harbour Tunnel are critical road links for Sydney’s transport system. Demand for these road links is expected to grow, increasing congestion. The proposed Western Harbour Tunnel and Warringah Freeway Upgrade would provide an additional crossing of Sydney Harbour to serve some traffic currently using the bridge and tunnel. It would also act as a western bypass of the Sydney CBD. In the absence of the project, travel times and congestion in this area are expected to increase significantly, and reliability will decrease.
The Western Harbour Tunnel and Warringah Freeway Upgrade involves construction of a twin three-lane motorway of 6.5 kilometres between Rozelle Interchange and the Warringah Freeway near North Sydney (the Western Harbour Tunnel) and upgrade of the Warringah Freeway corridor between the northern end of Sydney Harbour Bridge and Willoughby Road. The project as proposed in the submitted business case supports federal and state government priorities to
manage urban congestion in major cities.
The proponents proposed delivery approach, appropriately considers identified risks including, but not limited to, interface of Western Harbour Tunnel and Warringah Freeway Upgrade components of the project, differences in the nature of the works and skillsets required for each component, and market appetite, traffic management, and risks associated with tunnelling under Sydney Harbour.
Economic, social and environmental value
Overall, the project demonstrates strategic fit and strong economic, social and environmental merit.
The proponent’s business case states that the preferred project option would have a net present value (NPV) of between $827 million and $1,167 million and a benefit-cost ratio (BCR) of between 1.2 and 1.3, using a 7% real discount rate and P50 capital cost estimate. The outcome of the cost benefit analysis is sensitive to the choice of discount rate. Infrastructure Australia considers this an accurate view of the project’s net benefits, using appropriately conservative assumptions about future benefits.