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Frequently Asked Questions

What is the southern expressway duplication?

The Southern Expressway Duplication project transformed the one-way reversible expressway into an 18.5 kilometre multi-lane, two-way expressway between Bedford Park and Old Noarlunga.

The new carriageway was constructed on the western side of the existing roadway and will give northbound traffic two lanes from Old Noarlunga to Reynella and four lanes from Reynella to Bedford Park.

The existing carriageway will be used by southbound traffic with three lanes from Bedford Park to Reynella and two lanes from Reynella to Old Noarlunga.

How much did it cost?

The total cost of the project was $407.5 million.

What are the benefits?

The benefits of a duplicated Southern Expressway are:

  • greater travel efficiency and better access for commercial traffic to industrial areas and facilities in Adelaide’s south
  • improved access for people living in Adelaide’s south to employment, education, recreation and community facilities both in the south and the wider metropolitan area
  • reduced travel times and ease of journey to tourist locations along the Fleurieu Peninsula
  • two-way travel 24 hours a day, seven days a week, the length of the Southern Expressway
  • support for southern region economic development
  • improved road safety for commuters
  • improved emergency service access thanks to simultaneous north and southbound travel on the Southern Expressway.

Who paid for it?

The South Australian Government funded the duplication of the Southern Expressway.

Who were the contractors for the construction?

The Baulderstone Abigroup Joint Venture (BAJV) was awarded the Design and Construct contract for the Southern Expressway Duplication project.

Why wasn’t the road two-way when first constructed?

The Southern Expressway was originally constructed as a reversible road flowing in the peak direction to relieve congestion on Main South Road.

Was land acquisition required for the duplication?

No. The land used to duplicate the expressway was purchased by the State Government during planning for the original expressway in preparation for duplication of the expressway at some time in the future.

Expressway access and interchanges

Where can I access the Southern Expressway?

You are able to enter and exit the expressway at all existing interchanges including:

  • Main South Road, Darlington
  • Marion Road, Sturt
  • Panalatinga Road / Main South Road, Reynella
  • Sherriffs Road, Reynella
  • Beach Road, Noarlunga
  • Main South Road, Old Noarlunga

Construction Works

How long did the construction take?

The design and construction works took two years to complete.

What is the status of the design?

Major landscaping, noise attenuation treatments, pathways and urban design features were undertaken progressively throughout the works.

The project team engaged with local residents, community groups and businesses on design issues that directly affected them throughout the project.

Why are there reduced speed limits on the expressway?

Constructing a new road with complex construction works, within a narrow corridor and constantly changing traffic environment, while safely maintaining an operating road network has many challenges.

The current speed limits on the Southern Expressway have been implemented for the safety of all road users (road workers and motorists) and installed in accordance with Australian Standards and relevant guidelines, as required for construction works. The restrictions are necessary, regardless of the presence of workers, for several reasons including:

  • Reduced lane widths
  • Safety requirements whilst concrete barriers are under construction and temporary barriers are in place (resulting in reduced sight distances on curves)
  • Proximity of workers to traffic.

How was the community engaged throughout the project?

Community engagement was a high priority for the department during planning, design and construction of the Southern Expressway Duplication.

The project team is worked with community groups and local businesses affected by construction and engaged with local residents and stakeholders on specific design elements throughout the project.

Monthly updates were provided online, along with advance notice of construction activities for local residents, businesses, public transport commuters and road users.

Environmental Management

What was be done to manage construction noise and dust for residents?

Every effort was made to minimise the impact of construction. Local residents were advised that the project required the use of heavy, specialised and often noisy equipment.  Noise impacts were managed where possible using mitigation measures, such as turning engines and generators off instead of leaving them idle, this minimised the need for night works and monitoring noise and modifying work activities where possible.

During construction, dust was be managed in accordance with the Air Quality Management Plan and included management measures such as:

  • dust monitoring
  • use of water carts to wet down soils, stockpiles and access roads
  • stop-work procedures during windy weather conditions
  • early installation of mulch and landscaping.

How is traffic noise be managed?

Noise was recognised as a key environmental issue with the Southern Expressway Duplication.  Noise modelling and assessments were undertaken and mitigation treatment requirements identified where noise was expected to exceed the Road Traffic Noise Guidelines.

How were sensitive areas be managed?

The department engaged with special interest groups and other government departments to assist with management of sensitive environmental areas during the planning and design phase of the project including:

  • Environmental Protection Authority
  • Department of Environment, Water and Natural Resources
  • Adelaide Mount lofty Natural Resources Management Board
  • local government
  • Friends of Warriparinga
  • heritage groups
  • Living Kaurna Cultural Centre
  • Friends of Living Christie Creek
  • Friends of the Lower Field River
  • Trees For Life
  • other local stakeholders

The department engaged with those groups throughout construction to ensure the works were carried out sensitive to these important areas.

Did the project impact the Remnant Vegetation at the Beach Road interchange?

The design of the new north bound off ramp at the Beach Road Interchange included a retaining wall to minimise impacts to the remnant Grey Box woodland.  Tree protection measures were put in place during construction.

Project statistics

  • 7000 holes bored to accommodate blasting with up to 250 tonne of explosive product.
  • 1.6million m³ of cut to fill
  • 12 000 litres of diesel used every day and up to 20 000 litres at peak
  • 200 000 tonnes of asphalt will be used
  • 32 km of slip form barriers being installed on the live Expressway.
  • 8326 m³ of concrete.
  • 1403 tonnes of steel used in the bridge structures and retaining walls.