Travel demand across Sydney Harbour and onto the Northern Beaches is projected to increase, resulting in further congestion. Congestion on these corridors impacts on bus and private vehicle travel, with bus travel particularly impacted by congestion on the Spit Bridge/Military Road. The high levels of demand for existing infrastructure reflects the channelling of traffic onto the Sydney Harbour Bridge and Tunnel across Sydney Harbour, and the Spit Bridge and Roseville Bridge across Middle Harbour.
The 2019 Australian Infrastructure Audit ranks the North Sydney–Northern Beaches Corridor as the fourth most congested corridor in Sydney’s PM peak periods during 2016, and forecast seventh most congested in 2031, as measured by total vehicle delays. The Gore Hill/Warringah Freeway/Sydney Harbour Bridge/Eastern Distributor Corridor is projected to become the 10th‑most congested corridor in Sydney in 2031.
The initiative proposes a motorway crossing underneath Sydney Harbour, connecting WestConnex with the Warringah Freeway, and a motorway connection from the Warringah Freeway and Gore Hill Freeway to Seaforth/Balgowlah on the northern side of Middle Harbour.
Proponent to complete business case development (Stage 3 of Infrastructure