Basic Tunnel Info



The facts on the tunnel plans are:


  • Construction to take 5-7 years, starting in 2020-2021
  • Estimated cost of $8-10 billion
  • Unfiltered exhaust stacks at each tunnel entrance
  • Exhaust stacks will be approximately 8-10 storeys tall and located at the ends of the tunnels in Seaforth, Balgowlah and Cammeray. The stacks will release unfiltered exhaust from vehicles travelling the 7km length of tunnel, and there is no filtration of air either within, or outside the tunnel.
  • Balgowlah Golf course used as a construction site and converted to a multi-lane access road. The full green space will no longer exist, Burnt Bridge Creek and habitat will be moved 50 metres east, and over 550 mature trees will be removed.
  • Tunnel entrance near Kirkwood St, Seaforth impacting nearby residents with heavy truck movements and threatening endangered plant species and aboriginal rock art sites.
  • Kitchener St bridge widened, along with other road configuration changes near tunnel entrances. This includes only one lane of traffic towards Mosman on Burnt Bridge Creek Deviation that avoids the toll, and a new traffic light in the middle of Burnt Bridge Creek Deviation, creating rat-runs in local streets.
  • Construction sites for 5-7 years undertaking drilling, rock crushing, concreting and earth removal located at Balgowlah Golf course, near Kirkwood St, Seaforth and at Spit Reserve West, Mosman.
  • Steel and concrete tunnel tubes fabricated on a large pontoon stationed at Spit Reserve West, with tubes constructed on small stilts on the bed of Middle Harbour. Construction performed with the use of coffer dams and barges in the harbour.
  • Public transport not considered as an alternative to the tunnel
  • Toll for using the tunnel estimated at $5 each way in today’s money ($6.50 when open)(1)– with projected tolls estimated to the CBD of $23 return, airport $33 return and Blue Mts $60 return. This equates to over $5000 per year for a commute to the city, and much more to western Sydney.
  • Government estimates of travel time savings at 14 minutes from Seaforth to Cammeray, if there are no other influences to traffic flow, and estimates are realised.
  • Government estimates of just 15% reduction in traffic on the Spit Rd/Military Rd corridor


RMS map of Balgowlah Portal from draft reference design


RMS map of Seaforth Portal from draft reference design

1) Revealed: $8 tolls each way planned for new roadway tunnels to Sydney’s north (SMH, July 18, 2017)