The South Australian Government has made design revisions to the Torrens to Darlington project, focusing on improving connectivity and safety while safeguarding the fabric of the local community.

Once finished, it will complete 78km of non-stop motorway between Gawler and Old Noarlunga, and allow motorists to avoid 21 existing sets of traffic lights between the River Torrens and Darlington. The commute from West Hindmarsh to Darlington will take just nine minutes, saving 30 to 40 minutes of travel time during peak hour traffic.

The River Torrens to Darlington project is estimated to cost $15.4 billion, approximately $300 million more than the Liberals’ original concept.

The new design will include two tunnels and delivers upon three key objectives:

  1. Improved connectivity: the revised design will reduce congestion on parallel routes such as Goodwood Rd and Marion Rd, while allowing improved access to east-west connector routes, facilitating swifter and easier passage to the airport, Port Adelaide and the CBD, along with new pedestrian and cycling paths
  2. Improved safety: the southern portal of the Southern Tunnels has been shifted about 300m north to improve safety and connection with the Darlington Upgrade Project, while other entry and exit points are improved to ensure motorists will be able to safety enter and exit the motorway at more locations
  3. Safeguarding the fabric of the local community: large elevated structures have been cut from the original concept, improving visual amenity with less intrusive solutions.
    Following strong negative feedback about their visual impact on local communities, a citybound elevated ramp at Anzac Highway, and another next to the Brickworks Marketplace at Torrensville, will be replaced with design solutions that will enhance accessibility for commuters, avoiding potential bottlenecks and improving the visual amenity for those who live and work along the roadway and its surrounds

Key proposed changes to the Project include:

Torrensville area 

At the northern portal of the Northern Tunnels, near where the River Torrens to Darlington Project connects to the North-South Motorway, a proposed large elevated roadway running parallel to the Brickworks Marketplace has been removed, with the motorway corridor moving to the east. Instead, a shorter, low-height structure over the corner of the Hindmarsh Cemetery will be constructed. This improvement, along with changes to the construction methodology, means the Project will require less of Kings Reserve during construction than previously planned. Some residential properties originally earmarked for acquisition will no longer be needed.

James Congdon Drive/Deacon Avenue

An additional exit ramp for vehicles travelling north has been added near this intersection, providing access to Richmond Road and James Congdon Drive. This means vehicles travelling from the south, heading north to go to Adelaide Airport or the western suburbs do not need to go through the Anzac Highway intersection, greatly reducing the number of vehicles on the surface road there and increasing travel options for motorists. An additional entry ramp at James Congdon Drive has also been provided for traffic wanting to enter the motorway and head south, again reducing the number of vehicles travelling through the Anzac Highway intersection. These new inclusions will improve travel times for motorists.

Anzac Highway connection 

The elevated ramp going over the north-south motorway and South Road, before coming down onto the middle of Anzac Highway at Ashford to join with citybound traffic, has been scrapped. Instead, three ground-level right-turn lanes onto Anzac Highway heading towards the city will be provided, with an additional exit ramp from the River Torrens to Darlington motorway for northbound traffic, north of the Anzac Highway intersection. Right turns from Anzac Highway onto South Road – which were removed in the 2021 Reference Design – have been reinstated, acknowledging strong community feedback. This solution reduces traffic at the Anzac Highway intersection and the number of trees needing to be removed (approximately 35 instead of 116).

Darlington connection 

The southern portal of the Southern Tunnels will shift about 300 metres to the north to give traffic more distance and time to safely change lanes, while moving into and out of the new motorway. This provides the opportunity for better cross-corridor movement via a shared-use bridge, significantly reduces the duration of required closures of the Darlington motorway during construction (easing disruption for motorists) and reduces the length of the Southern Tunnels and the associated construction costs.


South Australian Premier, Peter Malinauskas, said, “This is the biggest infrastructure initiative in our state’s history, so it was crucial we took a diligent and thorough approach, when you’re building multibillion dollar tunnels through a highly urbanised corridor, there is only one chance to get it right.

“The State Government is committed to delivering the Torrens to Darlington motorway safely and efficiently to complete the 78km North-South Corridor, it is a vital project to the future of South Australia’s road network,” Mr Malinauskas said.

“Significant changes were needed from the design proposed by the former Liberal government in November last year, which simply could not have been delivered as designed and costed.” 

The new design also prioritises open green space and community areas along the alignment, with parts of the land required only during the construction phase planned to be repurposed after completion of the corridor to provide more canopy along South Road and the motorway, as well as areas which can be used by local communities.

The updated design has a revised estimated budget of $15.4 billion, as part of an overall package that also includes essential network upgrades that were not included in the 2021 Reference Design and which must be completed to ensure the road network functions during construction and the motorway operates effectively and safely as part of the broader network once complete.

The review also revealed the 2021 Reference Design could not have been constructed as designed for $9.9 billion. That design would have cost $14.3 billion, without the essential network upgrades which have been included in the updated design, which would have cost around an additional $850 million for an overall total of $15.15 billion.

SA Minister for Infrastructure and Transport, Tom Koutsantonis, said, “The Government has delivered on its commitment to re-examine this project to make sure that it constitutes the best solution for both motorists and nearby residents, and that it represents value for money for South Australian taxpayers.”

The State Government will work with the Commonwealth with a view to securing funding for a 50:50 split across the life of the project, making the state’s contribution around $700 million per year on average over the next decade.

The Government will now embark on a comprehensive engagement campaign with local communities to gather their insights into how the design changes affect their neighbourhoods.

The project review has also recommended a revised delivery program, which will see construction of the Southern and Northern Tunnels undertaken sequentially, rather than with an overlap, in a more realistic approach to project timing and market capacity.

Early works are underway, with main construction works proposed to start in 2025, with tunnel-boring machine (TBM) works for the Southern Tunnels planned to begin in 2026 and project completion expected in 2031.

Mr Koutsantonis said, “What we are announcing does just that, and our changes have been independently reviewed and verified as the way to move forward with this once in a generation project. It’s also important that we listen to community feedback and look closely at how the motorway will practically affect people’s lives.

“We’re now doing what should have been done in the first place, coming up with a sound, workable design focused on better connectivity, enhanced safety and safeguarding community. We will now be engaging genuinely with the community to seek feedback on the new design solution.

While some properties formerly earmarked for acquisition will no longer be required to deliver the new project, the design upgrade will result in a net increase of properties required to construct the River Torrens to Darlington motorway.

It has been found that the number of acquisitions previously announced by the former Liberal government was misrepresented as 393, the review instead revealed that a total of 412 full and partial acquisitions would be required.

The updated design has resulted in a further net increase in land acquisition to accommodate the amended design, essential scope and network upgrades to ensure the project can be safely and efficiently constructed.

In all 125 new acquisitions are required, with 13 properties no longer needed to be acquired. A total of 524 full and partial residential and commercial property acquisitions will be necessary to facilitate this project successfully.

The South Australian Department for Infrastructure and Transport is engaging sensitively with all owners and tenants impacted by the changes to the project’s design and will take a flexible approach to property acquisition wherever possible. The Department, in line with recommendations of a recent Public Works Committee inquiry, has endeavoured to contact all affected residents and businesses about any changes affecting them prior to the public announcement.

The approach will ensure people can stay in their homes for as long as possible, with partial acquisitions to be worked through in close consultation with homeowners, who will have the option to sell the entire property if they prefer to.

In early 2023, the River Torrens to Darlington Project will undertake a series of community information sessions along the alignment to engage with interested stakeholders and gain local insights to further inform the Project’s design. Details on these sessions will be communicated early in the new year.

This project is expected to support around 5500 jobs per year during construction, with the Government committing that at least 90 per cent of the project labour will be provided by South Australian workers, with a focus on providing key roles for Aboriginal workers, apprentices, trainees and jobseekers who are long-term unemployed.

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