South Road starts at the intersection of the Port River Expressway and the Salisbury Highway in Wingfield.

It continues through Old Noarlunga (where Victor Harbor Road branches off) and runs parallel to the coastline of Gulf St Vincent.

At Normanville, it is known as Willis Drive for 2 km, then continues to Cape Jervis at its southern tip.

The Southern Expressway runs roughly parallel to Main South Road for 18 km between Darlington and Noarlunga and serves to reduce traffic congestion.

However, increasing frequency of commuter trains results in vehicle bottlenecks that are anticipated to worsen.

[7]: 54 In November 2005, the Royal Automobile Association (RAA) released its recommendations to the South Australian government in regards to the road network.

It is 3–4 km of elevated motorway running from the Port River Expressway to the intersection with Regency Road.

4 km of lowered motorway was built between the northbound and southbound lanes of South Road.

[13] The project included replacing a level crossing of the Outer Harbor railway line, with a new bridge in 2017.

[14] The Darlington Upgrade, an extension of the Southern Expressway through Bedford Park by use of a similar lowered motorway concept, was also identified at this time.

Both of these upgrades involved land acquisition to widen the road corridor, surface grade local carriage ways on the edges, and a lowered central roadway carrying the free-flow traffic below the crossing routes.

[11] An upgrade of Regency Road to Pym Street, the gap between the elevated South Road Superway and the (then) almost-completed Torrens to Torrens lowered motorway, was announced in May 2018, to be jointly funded by the state and federal governments.