in 2005, with previous reversible carriageway signage before reconstruction in 2014 South Road suffers from
traffic congestion due to its importance as one of Adelaide's main
arterial roads and bypasses. Between 1982 and 1984, an overpass was built at
Emerson Crossing, taking South Road over Cross Road and the
Seaford railway line. For a long time, this was the only grade separation on South Road, and one of very few in South Australia, removing congestion with Cross Road traffic and the railway line. However, increasing frequency of commuter trains results in vehicle bottlenecks that are anticipated to worsen. Queues on the exit ramps to Cross Road can extend into the through lanes on South Road. The rail crossing can be closed for up to 20 minutes in the peak hour. In November 2005, the
Royal Automobile Association (RAA) released its recommendations to the South Australian government in regards to the road network. South Road was found to be the poorest road in the state, registering a 2/10 on the RAA's scale. The recommendations given included $6 billion of funds to upgrade the roads of South Australia – with $1.5–2 billion to be spent on South Road alone. The RAA's plan for the road included a 6 km tunnel from Port Road all the way to the Anzac Highway underpass. The plan called for over/underpasses at six other major intersections and two rail crossings. Underpass, heading south, April 2012 In 2005, along with the decision to make a free flowing South Road, a decision was made to build an underpass for South Road to go under
Anzac Highway. Named the Gallipoli Underpass in line with the
ANZAC theme, construction started in 2007. The underpass opened in March 2009. To cut down on delays due to construction, an overpass was built at the same time for the
Glenelg tram line just half a kilometre to the south, which opened in 2009, significantly removing delays from the area. In August 2007,
Prime Minister John Howard announced that South Road was to be included in the
AusLink National Road Network, and pledged $1 billion in funding for the project between 2007 and 2020.
North–South Motorway The North–South Motorway is an incomplete motorway intended to replace South Road as Adelaide's primary north–south roadway. Running along the same road corridor as South Road and extending further north, the motorway has been progressively constructed in stages. As of November 2020, approximately 22 km of the total 35 km length has been completed. The first section of the motorway, known as the South Road Superway, was announced in October 2009. It is 3–4 km of elevated motorway running from the Port River Expressway to the intersection with Regency Road. The project started in 2010 and was completed in early 2014. Following the
2013 Australian federal election, the section of South Road between Torrens Road and the River Torrens was identified and funded for an upgrade. 4 km of lowered motorway was built between the northbound and southbound lanes of South Road. The Torrens to Torrens lowered motorway started construction in 2015 and opened to traffic in 2018. The project included replacing a level crossing of the
Outer Harbor railway line, with a new bridge in 2017. 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. The Darlington Upgrade began construction in 2016 and was opened in 2020. Main construction began in late 2019. The overpass opened at reduced speeds in March 2021. Preliminary plans for the final section stretching from the
River Torrens to Darlington (T2D), which would use a combination of deep-bored tunnels, lowered motorway and surface-level motorway, were announced in late 2020. T2D is under construction. ==Major intersections==