The existing expressway exclusively facilitates a reversible one-way traffic movement stretching from Darlington to Noarlunga. The $407.5 million southern expressway duplication project includes the design and construction of 18.5kms of roadway alongside the existing expressway carriageway to convert the one-way road into a multi-lane, two-way road from Darlington to Old Noarlunga to the south of Adelaide. The project also includes the extension and duplication of bridges, pedestrian walkways and interchanges located along the existing expressway, and construction of new ramps.
Construction started in December 2011 and is scheduled for completion by mid-2014. The Southern Expressway Duplication project is being delivered by Lend Lease.