Case Study

Road: M2 Motorway Upgrade Project (AUS)

Sydney’s M2 Motorway spans approximately 21 km from Baulkham Hills to North Ryde and is located in close proximity to densely populated residential areas.  In response to increasing demand causing the motorway to regularly run at capacity during busy periods of the day, planning approval requirements were issued in April 2009 for a formal Environmental Assessment covering a major upgrade project consisting of additional eastbound and westbound lanes, widening of both tubes of the Norfolk Tunnel and modifications to several major over bridges and road interchanges.


2008 - Present


Sydney, New South Wales


Leighton Contractors



Project Objectives:

SLR was commissioned to prepare the Environmental Assessment (Noise & Vibration) for the Upgrade Project and to provide on-going noise and vibration consultancy services associated with the construction and operation of the M2 Upgrade project.

Of particular significance was the management of the ground-borne noise and vibration impacts for residences located above the Norfolk Tunnel arising during critical night-time work phases, e.g. rock bolting, rock breaking, rock milling, etc, carried out during the tunnel widening.

Our Role

SLR undertook the following works:

  • Environmental Assessment: Noise and vibration impact assessment during construction and operational phases, including assessment of potential ground-borne noise and vibration impacts.
  • Design Phase: Operational noise predictions for detailed design phase of project including design of all noise mitigation relating to the project.  Mitigation included low noise pavement, new / increased height noise walls and architectural treatment of houses.
  • Construction Phase: Monthly assessment of potential construction noise and vibration impacts for out-of-hours works.  Attended noise monitoring to verify predictions. Acoustic design of temporary construction noise walls.  Acoustic design of noise curtains for widening of Norfolk Tunnel.
  • Post-Opening Phase: Post-compliance (operational) noise monitoring and residual property treatments – yet to be completed.