Mulgoa Road Upgrade Alliance

  • Snapshot

Mulgoa Road is the main arterial connection between Penrith’s CBD and the M4 Motorway, and one of western Sydney’s busiest corridors, carrying around 52,000 vehicle movements a day. Transport for NSW is widening and upgrading 6.5 kilometres of this corridor across two stages to ease congestion, improve safety and keep pace with the region’s rapid growth.

Turnbull Engineering is the designer in the Mulgoa Road Alliance, working alongside Transport for NSW and constructor Seymour Whyte to take the upgrade from concept through to construction.

  • Location
    Penrith, NSW

  • Alliance
    Transport for NSW, Seymour Whyte and Turnbull Engineering

  • Turnbull’s role
    Designer and Non-Owner Participant

  • Project Value
    $456 million (Stage 1 and Stage 2)

  • Program
    2022-2029

  • Project phase
    Concept design, detailed design and construction phase services

Project Overview

The Alliance is delivering the upgrade in stages. Stage 1, between Jeanette Street and Blaikie Road, widened Mulgoa Road from four to six lanes — three in each direction — and improved access to and from the M4 Motorway. It was delivered ahead of time and on budget.

Stage 2, between Jeanette Street and Glenmore Parkway, is now underway. It replaces the Glenmore Parkway roundabout with traffic lights and adds turning lanes, dedicated bus lanes and a shared path, with completion expected in 2028–2029.

  • Scope

Services

As the Alliance designer, Turnbull Engineering delivered the full design scope across the corridor.

 

  • Road Design

  • Pavement design

  • Drainage Design, including flood improvements 

  • Structural design of underpass widening, retaining walls and noise walls

  • Utility coordination and design

  • Traffic management plans

  • Design of construction staging and temporary structures

Project Highlights

  • Integrated alliance delivery

    Delivered through an alliance that brings the designer, constructor and client into a single team — aligning design decisions with constructability and program from day one, and keeping a complex, live-traffic corridor moving throughout.

  • Designing around live traffic

    Design had to keep tens of thousands of vehicles flowing while the road was rebuilt around them — including staged construction design, structural widening at the M4 underpass, and coordination of around 8 kilometres of relocated utilities spanning water, sewer, gas, electricity and telecommunications.

  • Delivered ahead of schedule

    Stage 1 was completed ahead of time and on budget, with crews investing more than 743,500 hours into the works.

  • Built with sustainability in mind

    Environmental outcomes were a focus throughout, with more than 130,000 tonnes of material recycled during construction.

  • Client Feedback

“Stage 1 … delivered ahead of time and on budget is an important step forward.”

Prue Car
NSW Deputy Premier and Minister for Western Sydney

By the numbers

6.5 km

corridor upgraded

$456M

combined alliance value

52,000

vehicles per day

4 → 6

lanes (3 each way)

Next

Sydney International Speedway