South Australia’s busiest freeway corridor is getting a long-overdue fix. A $150 million rebuild of the Mount Barker and Verdun interchanges on the South Eastern Freeway is now underway, with night works active at both sites since early 2026.

The federal government is covering $120 million of the bill, with South Australia pitching in $30 million on an 80:20 split. Night works kicked off at Verdun on 22 February 2026 and at Mount Barker from 1 March. Both interchanges are scheduled to open to traffic in late 2027, according to the SA Department for Infrastructure and Transport.

The scale of the build is considerable. At Verdun alone, contractors will lay more than 20,000 tonnes of asphalt and 13,000 tonnes of granular pavement, and install 2.25 kilometres of new stormwater pipes. A new bridge spanning 13.45 metres over the westbound freeway exit underpass will be supported by 26 concrete piles and 12 bridge planks. South Australian company Bardavcol holds the Mount Barker contract; a joint venture between BMD Constructions and Leed Engineering and Construction is delivering Verdun.

The upgrades address a corridor that’s buckling under its own traffic load. Around 46,000 vehicles travel from Verdun into Adelaide daily, and the Mount Barker interchange handles about 31,200 a day. Between 2019 and 2023, crashes at Mount Barker were recorded repeatedly, with congestion and queuing a persistent problem. The Post SA confirmed the interchange work is part of a broader wave of 2026 road projects across the Adelaide Hills region, with the Verdun interchange currently lacking full access.

A separate $40 million state-funded upgrade of the Mount Barker roundabout at Adelaide Road, Alexandrina Road, Wellington Road, and Flaxley Road is running alongside the freeway works, adding to the pipeline for local civil contractors.

For SA tradies in civil construction, the work is live and hiring now. The project is expected to support around 260 full-time equivalent jobs per year across both sites, with concreters, pavers, earthmovers, and bridge specialists the most in-demand trades. Two SA-based firms are leading delivery, which puts local subcontractors experienced in road and bridge work in a strong position before the 2027 deadline.

Frequently asked questions

Who is funding the Mount Barker and Verdun interchange upgrades?

The federal government is covering $120 million and the South Australian Government is contributing $30 million, an 80:20 funding split.

When will the Mount Barker and Verdun interchanges open?

Both interchanges are scheduled to open to traffic in late 2027, according to the SA Department for Infrastructure and Transport.

Which companies are building the interchanges?

South Australian company Bardavcol holds the Mount Barker contract. A joint venture between BMD Constructions and Leed Engineering and Construction is delivering the Verdun interchange.

How many jobs will the project create?

The project is expected to support around 260 full-time equivalent jobs per year across both sites during construction, with concreters, pavers, earthmovers, and bridge specialists most in demand.

Sourced from Infrastructure Magazine, SA Department for Infrastructure and Transport, The Post SA. Original article.