Romeo Road West
Romeo Road West is a 1.9km dual-carriageway arterial in Alkimos, within the City of Wanneroo. Forming the northern terminus of the Mitchell Freeway and connecting west to Marmion Avenue, the project completes a critical link in Perth’s northern road network and opens the Alkimos growth corridor. As a designated Regional Road under the Perth Metropolitan Regional Scheme, its delivery is central to supporting long-term urban expansion.
Delivered during the convergence of three major state infrastructure projects – the Mitchell Freeway Extension, Yanchep Rail Extension and Alkimos Seawater Desalination Plant – the project required a highly coordinated, multi-stakeholder approach. Cossill & Webley designed Romeo Road as a subconsultant to the Mitchell Extension Joint Venture (MEJV) Alliance, while also acting as civil engineers for DevelopmentWA across Alkimos Central. This dual role provided the historical context and established relationships with stakeholders needed to coordinate the road design with the adjacent state projects and infrastructure.
The design integrated a widened service corridor to accommodate major utilities, including DN1400 desalinated pipeline, DN900 potable water distribution pipe, wastewater and high-voltage electrical infrastructure, while maintaining a high-quality streetscape with a central median wide enough for meaningful tree planting. Romeo Road also crosses the Yanchep Rail Extension via a new bridge designed by the NEWest Alliance, with Cossill & Webley contributing design requirements to carry essential services through the bridge deck, and separately designed a temporary diversion to maintain live water supply during construction.
A key challenge emerged when a group of limestone pinnacles of heritage value was identified directly within the planned alignment. With the Marmion Avenue intersection fixed, Cossill & Webley undertook a full realignment of Romeo Road, diverting the corridor south to preserve the pinnacles while maintaining safe and compliant arterial geometry.
The result is a carefully resolved piece of infrastructure that balances technical complexity, environmental sensitivity and the demands of a rapidly evolving growth corridor.
