CPB Contractors, McConnell Dowell, Arup and Jacobs to deliver $700m Kwinana Freeway upgrade

Perth's Kwinana Freeway is set for its next round of extra lanes. Main Roads WA has awarded the contract for the $700 million Kwinana Freeway Upgrade to a consortium of CPB Contractors, McConnell Dowell Constructors, Arup Australia Projects and Jacobs Group, which will upgrade more than 29 kilometres of freeway between Roe Highway and Safety Bay Road.

The award was announced on 28 August 2026 in a joint statement from the Australian and Western Australian governments, a month after the same consortium was named preferred proponent on 26 July. The award moves the project into detailed design, with construction to begin in early 2027 once environmental approvals are complete. Significant sections of widened freeway are scheduled to open by late 2028, and the whole project is due for completion in mid-2029.

Project at a glance

What is being built

The upgrade targets the freeway's busiest pinch-points with new lanes in three places. According to CPB Contractors' parent CIMIC Group and Main Roads WA, the works include:

• A new 11 km lane in each direction between Russell Road and Mortimer Road, taking the freeway from two lanes to three each way

• A new 2.5 km southbound lane and bridge widening between Roe Highway and Berrigan Drive, taking that section from four lanes to five
• A new 3.3 km northbound lane from Russell Road to Beeliar Drive, taking that section from three lanes to four
• Civil and Intelligent Transport System works for 11 new coordinated ramp signals on the northbound carriageway
• Improvements to noise walls, safety barriers, surfacing and drainage

The concept design also covers Principal Shared Path alignment and connections for people walking and riding along the corridor.

Extending the smart freeway

Ramp signals are traffic lights on freeway on-ramps that switch on when traffic is heavy. Vehicles queue on the ramp and are let onto the freeway, typically one or two at a time, with the timing adjusted to real-time conditions to keep the main lanes moving. The 11 new northbound ramp signals will create 42 km of continuous smart freeway from Safety Bay Road all the way to the Narrows Bridge.

The Kwinana Freeway carries about 100,000 vehicle movements every weekday, and Main Roads WA says 10 to 15 per cent of daily traffic is heavy freight. The extra lanes and managed on-ramps are designed to smooth peak-hour flows, cut travel times and improve safety for commuters and freight moving through Perth's growing southern corridor.

The team delivering it

The consortium brings together two construction contractors and two engineering consultancies. When the project went to market in October 2025, the expressions of interest sought "suitably qualified design and construction partners", and shortlisted contractors and consultants were invited to submit detailed proposals in March 2026.

CIMIC Group said on 9 September that the contract will generate revenue of approximately $250 million for CPB Contractors. CPB Contractors Managing Director Craig Nuttall said the contractor would take a staged approach to minimise disruption for motorists and would work closely with local communities.

Main Roads WA is also working with the Gnaala Karla Booja and Whadjuk Aboriginal Corporation to make sure heritage values are considered and protected as the design is refined.

What's next

Detailed design is the consortium's first job, and it includes a fresh look at noise. Main Roads WA says the delivery contractor will review noise levels under State Planning Policy 5.4 as the detailed design develops, with landowner consultation on noise treatments.

Environmental approvals are progressing in parallel. The project is being assessed under the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999, and public comment on its preliminary documentation and offset strategy closed on 21 August 2026. A state native vegetation clearing permit is also being processed.

Once approvals are in place, work on site is scheduled to begin in early 2027. Drivers in Perth's south can expect the first widened sections to open from late 2028, with the full upgrade complete in mid-2029.

Published 7 October 2026 · Updated 2 October 2026