Mickleham Road: delivering a safer corridor for Melbourne’s north

How early collaboration reduced delivery risk and expedited major works completion

More than 25,000 vehicles use Melbourne’s Mickleham Road every day, and rapid housing growth across Mickleham, Greenvale, Yuroke and Craigieburn has intensified pressure on a corridor that was no longer meeting current demand. As traffic increased, the single-carriageway arterial became a growing source of congestion, travel-time unreliability and safety issues at major intersections.

The Victorian Infrastructure Delivery Authority (VIDA), formerly Major Road Projects Victoria (MRPV), responded with a staged upgrade as part of Victoria’s Big Build programme. Stage 1 focused on the section between Somerton Road and Dellamore Boulevard, addressing key bottlenecks to improve safety and delivery.

Stage 1: addressing bottlenecks and improving safety

In 2022, we were appointed lead designer for Stage 1, working on behalf of the contractor under a Program Delivery Approach (PDA). Our team progressed the client’s reference design through detailed design, delivery support and as-built outcomes.

By bringing the client, contractor and designer together early, the PDA allowed risks, staging constraints and cost implications to be tested before major delivery decisions were locked in.

Stage 1 delivered a substantial package of safety, capacity and active transport improvements, including the duplication of 2.2km of Mickleham Road and 1.2km of Somerton Road, upgrades to four congested intersections at Somerton Road, Aitken College, Hillview Road and Dellamore Boulevard, and more than 10km of new lanes. The works also replaced the Somerton Road roundabout with a signalised intersection and delivered new and upgraded cycling and walking paths.

Jointly funded by the federal and Victorian governments, the A$220-225M programme delivered long-awaited safety and capacity improvements for this critical north-south corridor.

Designing for certainty in a constrained corridor

The PDA embedded collaboration at the start of delivery. During an initial 12-week development phase, the integrated team refined the reference design into a preliminary detailed design, testing cost, risk and constructability before construction decisions were locked in and reducing the likelihood of rework.

Our multidisciplinary team helped turn the reference design into a construction-ready solution that balanced road geometry, utilities, drainage, structures, construction requirements and asset acceptance requirements. Our scope included road widening and alignment design, intersection reconfiguration, drainage, flood modelling, culverts and retaining structures, utility relocation coordination, including the Melbourne Airport jet fuel pipeline, and construction-phase design support and design assurance.

Several design decisions show how the collaborative model created value in practice, making the design easier to deliver while strengthening the corridor's long-term corridor performance. These included:

• Optimising alignment to reduce reconstruction
  
  One critical design decision was to adjust the alignment so the project could reuse as much of the existing pavement as possible. This supported an overlay approach instead of full-depth reconstruction, reducing construction time, material use and cost while managing constraints around property tie-ins, existing services and drainage systems.
  
  
• Managing flood risk and compliance
  
  Meeting Melbourne Water’s stringent flood and afflux requirements was one of the project's most complex challenges. Road duplication changed overland flow paths and flood behaviour across the corridor, requiring iterative modelling, design refinements and regulatory approvals. To support faster assessment and clearer reporting, we developed a GIS-based approach that linked afflux modelling outputs directly to individual properties, enabling rapid property-level assessment across hundreds of locations.
  
  
• Enhancing local connectivity
  
  As part of design development, we delivered a new road link between the previously disconnected Aspect and Providence estates. Although short, the link required the team to resolve land, utility and stakeholder constraints. It improved local access by reducing travel distances and connecting neighbouring communities more directly, with minimal additional cost.
  
  
• Embedding sustainability in design
  
  Our sustainability contribution focused on incorporating recycled materials into the design, including recycled aggregates. This supported broader contractor-led sustainability initiatives during delivery, including topsoil reuse and lower-carbon construction approaches.

An intersection on Mickleham Road before upgrades (image credit: Victorian Infrastructure Delivery Authority (VIDA)).

An intersection on Mickleham Road before upgrades (image credit: Victorian Infrastructure Delivery Authority (VIDA)).

An intersection on Mickleham Road after upgrades (image credit: Victorian Infrastructure Delivery Authority (VIDA)).

An intersection on Mickleham Road after upgrades (image credit: Victorian Infrastructure Delivery Authority (VIDA)).

Ahead of schedule and ready for growth

Stage 1 has enhanced safety, traffic flow and reliability at key intersections, while improving access to schools, services and local communities. Completed six months ahead of schedule, the upgrade demonstrates how early collaboration under the PDA model helped improve delivery certainty and reduce disruption.

As the client progresses Stage 2, our Stage 1 work helps set up the next phase of the corridor's growth. The design incorporated a ‘stub’ at the northern end so future duplication can connect seamlessly. By April 2025, funding for Stage 2 had been confirmed, with construction expected to begin in 2027.

The Mickleham Road Upgrade – Stage 1 shows how thoughtful design decisions within a collaborative PDA delivery model can deliver meaningful value beyond standard road duplication. Early alignment between client, contractor and designer reduced delivery risk, resolved practical delivery constraints and addressed complex environmental challenges while preparing the corridor for future expansion. For Melbourne’s growing north, the result is a safer, more reliable corridor designed for current demand and the next stage of growth.