WestConnex is part of an integrated transport solution to address the needs of a growing city

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FAQs See all

Transferring vehicles from surface roads into free-flowing underground motorway tunnels will improve the air quality along existing surface roads where traffic is reduced.

For example, an independent air quality assessment detailed in the M4 East EIS found air quality will generally improve along the Parramatta Road corridor because of traffic shifting to WestConnex.

Motorists will have a smooth motorway to travel on, rather than being stuck in congested, stop-start traffic with traffic lights, and this will reduce emissions.

Our tunnels are also designed to reduce emissions, as they are generally flatter and less steep at the entries and exits.

We fully recognise the importance of Sydney Park and the investments that the City of Sydney Council and others have made in recent years.

A strip of land owned by Roads and Maritime Services adjacent to Sydney Park is being used to widen Euston Road as part of local road upgrades. This is not part of Sydney Park.

As outlined in the City of Sydney’s own management plan for Sydney Park, this land is dedicated road space and has been subject to a long-standing road widening reservation.

A small boundary strip, adjacent to the road reserve, is also required for the local road widening, however this is more than offset by the additional 8.5 hectares of open green space being created at St Peters Interchange.

Two hectares of this open green space will be directly connected to Sydney Park via a land bridge over Campbell Road.

Traffic modelling tells us the expected demand for WestConnex and the number of traffic lanes needed. The motorway has been designed to meet traffic demand now and in the future.

The number of lanes varies across the project: 

  • M4: the M4 Motorway has been widenedfrom three lanes in each direction to four lanes in each direction between Parramatta and Homebush. The new M4 East tunnels between Homebush and Haberfield will be three lanes in each direction.
  • New M5: when the tunnels open, there will generally be two lanes in each direction between Kingsgrove and St Peters. The tunnels can accommodate three lanes in each direction in future, with additional approvals needed for this change.
  • M4–M5 Link: The M4-M5 Link will provide twin underground tunnels with four lanes in each direction between Haberfield and St Peters.