M4 Widening, WestConnex

Efficient, pleasurable and contextual transport modes are key to a successful city. With Sydney’s western suburbs continuing to expand both in terms of population and footprint, the Westconnex motorway is a critical piece of public infrastructure.

DesignInc provided architecture, urban design and landscape services for widening a 7.5km stretch of existing motorway in the Granville area. Project scope included upgrading existing interchanges, construction of a new 1.8-kilometre viaduct, new bridges over Duck River and Deniehy Street, retaining walls, 4.9 kilometres of noise barriers and a new stretch of shared path/cycleway.

Elegance and efficiency

Given traffic congestion and population growth along this stretch of Western Sydney, project goals were to minimise noise and visual impacts on the adjacent community, improve the visual experience of the motorway and activate forgotten spaces under existing viaducts, with improved wayfinding signage and street furniture.

Location: Dharug Country
Homebush Bay, New South Wales
Client: Transport for NSW
Scale: 7.5km
Year: 2018
Project Contact: Mary Anne McGirr
Photography: Bird Drone Photography
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DesignInc Sydney - M4 Widening, WestConnex

Colour and pattern

Simple but strong architectural elements will integrate the new bridges, interchanges, retaining walls and noise barriers with existing motorway elements. A secondary layer of expression through colour and pattern will embed the new elements into local landscapes.

Colour, form and finishes for the new urban design elements will help them interact dynamically with existing structures to improve journey legibility and experience. At the Silverwater Road Interchange, a pair of patterned, cantilevered walls reference the local industrial context through their abstracted pattern of steel truss forms.

We achieved some great urban outcomes on the WestConnex M4 Widening project—improving the journey experience, minimising visual impacts, activating forgotten spaces and improving legibility, wayfinding and safety for motorists, cyclists and pedestrians.
Mary Anne McGirr
Director, DesignInc Sydney

Softening with landscape

Viaduct and bridge piers both reference and contrast existing adjacent viaducts, with their clean lines and smooth circular piers. On the viaduct and at interchanges, noise walls reference the colour of a Cumberland Plain native flower—Sarsparilla Hardenbergia violacea, with more neutral colours applied to noise walls facing into residential areas.

Recognising the limited planting opportunities in narrow corridors, the landscape maximises impact at the interchanges with mature native plantings.