The Westconnex-Sydney Tunnel connects the M4 to the M8, bypassing 52 traffic lights for $5.65

A tunnel under Sydney is expected to save commuters up to 40 minutes of travel time when it opens early next year.

Westconnex’s ‘Missing Link’ will connect the existing M4 and M8 tunnels, bypassing up to 52 traffic lights between St Peters and Haberfield and linking Sydney West to the airport.

Commuters can expect to travel the entire 7.5km tunnel in just eight minutes, and it’s forecast to cut the off-peak transit time between Parramatta and Mascot by up to 40 minutes.

Currently, commuters from Parramatta to Sydney Airport must exit the M8 at Homebush and join the A3 through Greenacre before joining the M5 at Roselands, a notional 30-40 minute journey which is normally choked with traffic.

Passenger vehicles will pay $5.65 to use the new link, which is a distance-based toll capped at $10.47 for use of the entire 21-mile West Connex network.

A 7.5km ‘world-class’ tunnel linking Sydney’s M4 to M8 will link Sydney’s west to the airport in early 2023

Transurban chief executive Andrew Head invited reporters and members of the surrounding community to tour the tunnel on Sunday.

“The concrete and steel have been laid, but right now we’re testing the tunnel,” Head told reporters.

“We have ventilation systems, we have lights, we have cameras, we have speakers, all the different things you need to ensure a safe journey.”

The tunnel has an automated accident prevention system that can detect a vehicle stopping or reversing in the tunnel and alert personnel and emergency services.

Numerous other safety technologies and systems have been introduced into the new connection, “related to fire, related to observing traffic, identifying incidents, and dispatching people to respond to those incidents as quickly as possible.” said Head.

Transurban Chief Executive Andrew Head told reporters pictured: “The concrete and steel have been laid but what we are doing at the moment is testing the tunnel.”

“This facility is truly world class and a real credit to the designers and everyone who worked on the tunnel,” said Terry Chapman, Transurban Project Manager.

Westconnex has also partnered with popular navigation app Waze to install more than 1500 navigation beacons on the M4, M8 and M5 East to ensure there are no ‘GPS blackouts’.

Heavy vehicles initially pay $16.95 to use the tunnel.

Future projects such as the Rozelle Interchange, Western Harbor Tunnel and Sydney Gateway will use the M4 to M8 link when completed.

Sydneysiders commuting between Parramatta and Mascot can expect to save up to 40 minutes thanks to the expected eight-minute journey the entire route (pictured, Sydney traffic).