Coolac Bypass – completed

The new $179 million Coolac bypass completes dual carriageway of the Hume Highway north of Gundagai. The project, which was officially opened on 14 August 2009, was funded by the Federal Government and managed by Roads and Maritime Services.


The Hume Highway is the main freight route between Sydney and Melbourne. It is also a vital transport link for communities and industries in southern NSW.

The Federal and NSW governments are committed to upgrading the entire length of the Hume Highway to a four lane divided carriageway by 2013.

The construction of the Coolac bypass, which commenced in May 2007, has been an integral part of this process.

This project was funded by the Federal Government and managed by Roads and Maritime Services.


  • Construction: Abigroup Contractors Pty Ltd
  • Site management: Professional Engineering Services Pty Ltd.

Points of interest

  • Approximately 1.6 million cubic metres of earthworks have been excavated and built into embankments
  • An on-site batch plant generated over 130,000 cubic metres of concrete throughout the project
  • Three concrete paving machines were used
  • At construction peak, the main paving machine generated over 500 metres of roadway – over 1000 cubic metres of concrete – in a single day
  • Over 50,000 native trees will be planted as part of the final project works
  • A total of 137 nesting boxes have been installed in some of the larger trees to help with the breeding of native birds
  • Six glider poles have been be installed to help with the safe movement of native fauna, such us the squirrel glider, between adjacent clusters of native vegetation
  • A travelling stock reserve has been provided adjacent to, but separated from the highway
  • A heritage-listed timber railway platform has been relocated from Pettit and permanently installed along a section of railway line opposite Coolac village
  • A length of the main trunk from a 150 year old survey-marker tree ('blaze' tree) was preserved and relocated to the Gundagai Historical Society, where it is now on display
  • Facilities have been constructed in the two rest areas at Coolac

Project benefits

The bypass significantly improves road safety by:

  • Providing a four lane, divided carriageway to separate northbound and southbound traffic
  • Removing heavy vehicle traffic from Coolac village and providing safer access from the Hume Highway to Pettit and Coolac
  • Reducing travelling times and heavy vehicle operating costs for through traffic.

Key features

  • Construction of 12 kilometres of dual carriageway on the Hume Highway
  • Reconstruction of four kilometres of northbound carriageway between Muttama Creek and the Dog on the Tuckerbox on an improved alignment
  • A full diamond interchange at Cootamundra Road, east of Coolac
  • An underpass for local traffic at Coleman Street in Pettit
  • Twin bridge structures at Muttama Creek and Daisy Bed Creek
  • The upgrade of Main Street and Gobarralong Road in Pettit
  • A rest area on either side of the highway, including landscaping and parking.

A better project

As the detailed design of the project has progressed, a number of modifications have been made to the proposal approved in 1997. These include:

  • Redesigning the Cootamundra Road interchange to reduce the amount of land required for acquisition.
  • Moving the location of the Travelling Stock Route between Muttama Creek and Pettit to the disused railway corridor.
  • Eliminating level crossing intersections between the Hume Highway and the Tumut – Cootamundra railway if the railway is reinstated.
  • Providing rest areas for traffic in each direction.
  • A minor realignment of the road in Pettit to accommodate drainage infrastructure.
  • Restricting access to the Hume Highway from Gobarralong Road to southbound traffic only. Main Street will be upgraded to connect to Coleman Street for northbound access onto the highway.
  • The location identified for the concrete batch plant to be the southbound rest area site.

1995 assessment

The proposal for the Coolac Bypass was the subject of an Environmental Impact Statement. This was exhibited for comment in 1995.

Submissions to the EIS and further geological investigations led to modifications to the project. The changes were to minimise the impacts of the low levels of asbestos present in the underlying rock of parts of the site and in the soils resulting from the weathering of these rocks.

The modified proposal was exhibited for comment in 1996 and received approval in May 1997, subject to a number of conditions.

2004 environmental review

Roads and Maritime Services completed an environmental review of the project in October 2004.

The review was conducted to:

  • Determine if the modifications are consistent with the 1997 planning approval.
  • Consider any impacts arising from the changes in the environment, legislation and government policy since the previous approval in 1997.
  • Assess any impacts that could result from the design changes.

The environmental review concluded that no significant impact to the environment is likely and a further environmental impact statement was not required. Some additional measures to reduce potential impacts on the environment were included. Approval to the environmental review was granted in November 2004.

A copy of the environmental review is available for view and download at the bottom of this page.

Management of asbestos bearing materials

Investigations during the environmental assessment of the project confirmed there are low levels of naturally occurring asbestos in the underlying rock and soil north of Muttama Creek.

The alignment and design of the project has been adjusted to minimise the possible disturbance of asbestos in this area.

A management plan has been developed to control the generation and transmission of dust, to protect both workers and residents during construction activities.


Comunity update - August 2009

August 2009

The new $179 million Coolac Bypass completes dual carriageway of the Hume Highway north of Gundagai.

Coolac Bypass map

January 2011

Hume Highway – Coolac Bypass map.

Coolac Bypass Environmental Review

October 2004

Coolac Bypass Environmental Review October 2004.

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