Road tunnels

Watch air quality specialist Andrew Mattes discuss tunnels and emissions

There are five main tunnels in the Sydney road network; Lane Cove Tunnel (M2), Sydney Harbour Tunnel, Cross City Tunnel, Eastern Distributor and the M5 East Tunnel. Each of these tunnels have elevated ventilation outlets which are very effective at ejecting tunnel air high into the atmosphere through a combination of buoyancy and speed, dispersing and diluting pollutants much more effectively than surface level emissions.

Learn why we build tunnels


Download tunnels factsheet (PDF)

Monitoring emissions

Tunnel air quality is monitored 24 hours per day in all new tunnels and compiled into real-time data and historical reports. That’s 8,760 hours of monitoring a year making sure air quality meets strict guidelines.

How our tunnels work

Free flowing traffic produces fewer emissions than stop start traffic. Ventilation outlets disperse emissions high into the atmosphere away from local communities. Click to find out more below.

Artist impression of emission levels and traffic are indicative only.