Reid Highway and Erindale Road Grade Separation

Reid Highway is a key east-west arterial road in Perth’s northern suburbs, linking two major north-south corridors: Mitchell Freeway to the west and Tonkin Highway to the east. Recent investments have focused on upgrading Reid Highway by progressively replacing at-grade signalised intersections with interchanges that enable free-flowing traffic.

The intersection of Reid Highway and Erindale Road is the last remaining at-grade intersection between Mitchell Freeway and Tonkin Highway. It plays a vital role in the broader road network, facilitating access to residential suburbs such as Hamersley and Warwick, as well as the Balcatta light industrial area.

This intersection carries approximately 83,000 vehicles per day and was ranked the most congested intersection in Western Australia in 2023/24. It also recorded the highest number of reported crashes in the Perth metropolitan area.

The project will see the last at-grade signalised intersection on Reid Highway at Erindale Road replaced with a bridge carrying Erindale Road over Reid Highway

By taking Erindale Road over Reid Highway, the project will improve safety by replacing the signalised intersection with a grade-separated interchange, reducing the likelihood and severity of crashes.

The project also proposes to significantly improve the daily commutes for residents in Balcatta, Hamersley, Warwick, and other northern suburbs, by easing congestion and delivering safer, more efficient roads.

Other key benefits include:

• Improved travel time reliability and productivity for freight traffic, particularly for access to the Balcatta industrial area
• Greater travel time consistency for all road users
• Improved accessibility and connectivity between Reid Highway, Mitchell Freeway, and Erindale Road
• Upgrades to the Principal Shared Path network, improving safety and connectivity for vulnerable road users including, pedestrians and cyclists.

Protecting the environment

Main Roads is dedicated to reducing environmental impacts throughout the planning, construction, and maintenance of road projects. Beyond minimising harm, we actively offset unavoidable impacts by procuring and rehabilitating suitable land parcels, ensuring a positive contribution to environmental sustainability.

We are undertaking studies and field assessments to understand environmental values within the proposed project extent to inform mitigation strategies.

The project will be referred to both the Federal and State environmental regulators below:

• Federal: Referral to the Federal Department of Climate Change, Energy, the Environment and Water for assessment of preliminary documentation under the Environment Protection and Biodiversity Conservation (EPBC) Act
• State: Referral to the Environmental Protection Authority (EPA) for assessment

Managing noise

Potential noise impacts are a key consideration when planning major road infrastructure.

Baseline noise monitoring and modelling is currently being undertaken which, combined with other factors such as proposed design levels, road surface type and predicted traffic volumes will identify the forecast noise levels at sensitive noise receivers in the vicinity of the project. Where acceptable thresholds are exceeded, this will guide mitigation options in accordance with State Planning Policy 5.4 “Road and Rail Transport Noise and Freight Considerations in Land Use Planning”.

Should physical mitigation requirements be identified (e.g. noise walls adjacent to properties) as part of the detailed design process, property owners will be consulted.

Project Updates

• Project Update - March 2026 - PDF (691 KB)

Funding

Funding of $450 million has recently been committed to undertake the development and delivery of these works, with 50/50 funding from the State and Federal governments.