South Road Superway
One of Adelaide’s largest and most complex road projects dramatically reduced congestion on the North-South corridor


At the time of completion, the iconic South Road Superway was South Australia’s largest and most complex road infrastructure project. It is a key component in the redevelopment of Adelaide’s critical North-South transport corridor to meet future needs. The project was jointly funded by the state and federal governments.

Leed delivered the project in a Joint Venture with John Holland and MacMahon Contractors.


This high-profile project delivered a 4.8 km non-stop corridor incorporating a 2.8 km elevated roadway—the first of its kind in South Australia—10 m above the existing South Road and supported by 68 concrete piers. Grade separations over four signalised intersections and a freight railway crossing were also undertaken. The project featured:

  • more than 2,200 precast concrete segments, weighing between 65 and 90 tonnes each, cast in a purpose-built, on-site casting yard
  • complex, novel works carried out in a highly trafficked, brownfield environment
  • the most advanced Intelligent Traffic System (ITS) used in South Australia at the time
  • significant traffic management along Adelaide’s busiest arterial road with temporary roads and major diversions to existing services
  • management of numerous and disparate stakeholders.

As part of an integrated team, Leed were involved at ground works in the construction of concrete structures, asphalt, pavements, drainage and service relocation, traffic control and traffic management, supervision of piling, electrical and ITS.

Key features

The project featured innovations in concrete design and construction. Pre-stressed, segmented concrete box girders were constructed in balanced cantilever, and supported on reinforced concrete curved pier substructures. In an Australian first, mid-span needle beam joints were used to provide deck articulatrion.

Another key feature was the use of continuous flight auger piles, using a high performance concrete mix design. This approach provides a 150-year design life despite challenging ground conditions.

Innovations in traffic management allowed additional works to be undertaken concurrently. Full traffic flow was maintained during peak hour, with no traffic accidents attributed to the staging. Design and modelling work for detours ensured functionality before implementation.


This project delivered an outstanding piece of infrastructure for South Australia, and dramatically reduced congestion on one of the state’s most important transport corridors. The Superway connects industry to air and sea ports, meets future residential and industrial demand and complements the long term growth of the area and Adelaide as a whole.


South Australian Engineering Excellence Awards

2016 Excellence Award for Project Infrastructure

Consult Australia Awards

2015 Design Innovation Award—High Commendation

Concrete Institute of Australia Awards

2015 National Award for Excellence in Engineering Projects

2015 Award for Excellence in Engineering Projects (SA)

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