Curves That Never Sit Still: The M7-M12 Interchange, Western Sydney

Two 660-metre bridges curve away from the Westlink M7 and bend in both plan and elevation as they go. They are the longest incrementally launched curved road bridges in Australia, assembled from 27 steel segments pushed out over live traffic. The interchange they form opened on 13 June 2026, linking the M7 to the new toll-free M12 Motorway and opening the corridor to the Western Sydney Aerotropolis and Western Sydney International Airport. Seven new bridges were built, the M7 was widened to three lanes each way between Richmond Road and the M5, and the southbound run from Marsden Park to Liverpool is now up to 13 minutes shorter. 

Feature lighting on a structure like this has to survive the traffic it sits above. Around 180,000 motorists use the M7 every day, and a motorway bridge under live load never stops moving. 

Our contribution focused on the two curved bridges, where 838 Aria RGBW luminaires run the feature lighting on a Pharos control system. The standard Aria bracket is adjustable, and adjustable would not have held here, so our R&D department designed a fixed bracket specifically for vibration resistance. The bracket and luminaire combination was tested on jigs built in-house for this project and independently verified, passing to 3G. R&D also built redundancy into the data path, customising the luminaire electronics with a bypass so that no single unit can interrupt a run of that length. 

The lighting scenes follow a cultural design narrative developed for the project by Aboriginal design consultancy BALARINJI, working with local Aboriginal artists, and the completed scenes reflect the six First Nations seasons of the area. Coolon's role was to make those scenes possible: the colour range and optical control of Aria RGBW, and a Pharos system that holds them steady and even across a structure curving in two directions at once. 

Jadecross supplied the luminaires and ran several lighting mock-up trials with the customer in the early stages, which is where the optics, aiming, spacing, luminaire length and power were settled. They also carried the project documentation across every stakeholder. 

Engineering solved the crossing. Lighting gave it a face after dark.