M5 Widening, Peer Review


Department of Planning & Infrastructure



Completion date

1993 & 2005

The M5 West Widening project expanded Sydney’s M5 South West Motorway from two to three lanes in each direction from King Georges Road, Beverly Hills to Camden Valley Way, Prestons. Approval for the project was subject to Conditions of Approval including management of a variety of impacts, including an assessment of noise mitigation requirements. However, in the Casula area at the west end of the project, there was heightened concern about the adequacy of existing and proposed noise mitigation.

Scope of Services

Marshall Day Acoustics was commissioned by the Department of Planning and Infrastructure to undertake a detailed review of the proposed noise mitigation requirements, including the history of noise mitigation outcomes dating back to the construction of the M5 in 1993 and the interconnected M7 in 2005.

Marshall Day reviewed over twenty documents dating back to 1992, including everything from multi-volume Environmental Impact Statements to five-page faxes. We inspected the most recent noise model for the M5 and spoke with people involved in the M5 West Widening noise assessment.

Because of the massive size of the historical projects, public documents did not provide enough detail to be certain of some details. Closing out of requests for information drew out the timeframe to several months, so Marshall Day provided interim advice for delivery to the Minister. The Department of Planning and Infrastructure praised this attention to detail, saying, “This was why we hired you.”