M12 Motorway (Central)

The M12 Motorway is a 16-kilometre, four-lane motorway connecting the M7 Motorway at Cecil Hills to The Northern Road at Luddenham, providing a vital transport link to the new Western Sydney International (Nancy-Bird Walton) Airport. The project is being delivered in three packages: the Western section, the Central section, and the Eastern section

The Central section, delivered by Seymour Whyte on behalf of Transport for NSW, includes major earthworks, bridge structures, and complex pavement construction through the centre of the corridor.

Dowsing Group was engaged to deliver large-scale diamond grinding and grooving treatments across the project’s pavement to achieve the required surface smoothness and ride quality.

Dowsing’s scope included conventional and flush diamond grinding, grooving, and feather grinding, all performed using calibrated grinding equipment with automated controls to achieve tight ride quality tolerances.

Dowsing successfully completed extensive diamond grinding and grooving works across the M12 Motorway Central section, contributing to the delivery of a high-performance pavement surface. The program achieved an average International Roughness Index (IRI) of 1.1, with some sections recording IRI values as low as 0.3 — an exceptional result for large-scale motorway construction.

Through daily pre-start coordination, calibrated machinery, and rigorous safety and quality management, Dowsing ensured all works were completed efficiently, safely, and to specification. The collaboration with Seymour Whyte exemplified best-practice delivery, resulting in a durable, smooth, and compliant pavement finish that supports the long-term performance of this critical transport corridor