An upgrade of three major highways is set to improve the safety and reliability of national freight routes in South Australia.

More than 3200 heavy vehicles a day use the Stuart, Augusta, and Dukes highways, which are vital transport corridors for freight crossing the nation.

About half of those vehicles are B-doubles and road trains.

The upgrades will also improve freight productivity by reducing travel times for the delivery of goods to businesses and the community, as well as reducing operating costs for commercial vehicles.

Initial works have started on the Stuart Highway, near the Northern Territory border, and along the Dukes Highway.

Other works along Port Wakefield Highway between Adelaide and Port Wakefield and on Augusta Highway around Port Augusta, will also be undertaken as part of $30m in upgrades occurring this financial year.

Planning for the remaining program is progressing, with other works being considered including intersection upgrades, overtaking lanes, rest areas and targeted safety treatments.

In total, $500m has been committed towards the upgrades, with the Federal Government committing $400m and the South Australian Government committing $100m.

The Federal Government’s contribution is part of the $1.5b National Freight Highway Upgrade Program – a 2022-23 October Budget commitment to seal the Tanami Track in Northern Territory and Western Australia, as well as upgrading other nationally significant freight routes, including the Dukes, Stuart and Augusta highways, and Central Arnhem Road in the Northern Territory.