The Victorian Government and Transurban understand that noise is an important issue for residents of Melbourne’s inner west and along the West Gate Freeway. Many are concerned about existing noise from trucks travelling through the local area and from the 200,000 vehicles that use the West Gate Freeway every day.

Meet Phil West, our noise expert.

Video transcript for Western Distributor – noise mitigation (DOCX 14kb)

What is noise?

Noise is generally defined as unwanted sound.

We all experience noise differently. Noise is measured on a scale of units called decibels, or dB for short. Noise measurements are usually adjusted to reflect how the human ear perceives noise. This results in a noise unit called ‘A’ weighted decibels, or dB(A).

Graph showing the dB(A) levels for noises such as a quiet bedroom (40 dBA), busy office (60 dBA), car at 70 kmh, 7m distance (75 dBA) and a heavy truck at 40 kmh, 7m distance (85 dBA)

Common noises and their impacts

Noise from traffic varies over times, both from second to second, and from day to night. The LA10 describes the noise level exceeded for 10 per cent of a specific period. For traffic noise affecting residential properties, the period is 18 hours from 6am to midnight.

Noise measuring and modelling

When measuring traffic noise we use professional acoustic consultants who follow best practice methodology, guidance and regulatory requirements. A variety of factors are taken into consideration when measuring and modelling noise:

  • traffic volume, speed and number of trucks
  • gradient (steepness) of the road
  • surrounding terrain, like hills or valleys
  • soft ground or hard pavement between the road and the receiver
  • distance from the road
  • shielding by structures such as noise barriers or buildings.

Did you know?

  • doubling of traffic volume increases noise by around 3dB(A)
  • an increase in noise level of 3dB(A) is only just audible to the human ear
  • an increase of 10 dB(A) doubles the perceived loudness of noise
  • reducing traffic speed from 100km/h to 80km/h reduces traffic noise by roughly 1.5 dB(A), if the traffic volume remains the same.

Noise regulatory requirements

Noise management, during construction and once the Western Distributor is open, is a critical part of the planning and design. A number of regulatory requirements are in place to protect the local community and ensure that any unavoidable impacts are well managed.

VicRoads Traffic Noise Reduction Policy 2005 outlines regulations regarding noise limits in order to limit noise impacts from new or upgraded roads.

The Western Distributor may have specific requirements relating to traffic noise determined as part of the planning process

Designing to minimise traffic noise

Noise walls and other measures will be required to minimise noise for residents as part of the Western Distributor project.

The design of noise walls, including the height and building material, is informed by detailed noise modelling which will be included as part of the Environment Effects Statement.

New or upgraded noise walls will be built to a high standard, with a life-span of at least 40 years and noise testing will be undertaken before and after the Western Distributor is built to ensure all noise walls are doing their job.

Feedback received through consultation will help to inform the appearance of new or modified walls, which will need to be in keeping with urban design guidance for the project.

In addition to noise walls, we are investing in traffic management technology and systems to improve traffic flow and reduce stop-start traffic that can cause noise.

Environment Effects Statement

The Environment Effects Statement (EES) being prepared for the Western Distributor will identify any potential noise impacts that need to be considered in decisions about the Western Distributor’s design, construction management and ongoing operations. This will ensure appropriate design of noise reduction measures, such as noise walls, to protect those living close to any new or upgraded sections of the road.

Detailed noise assessments will be carried out along the corridor of the Western Distributor to evaluate and predict the potential changes in noise due to the Western Distributor.

These assessments will help build our understanding of the existing environment so noise modelling can be done to understand and predict future noise levels on the West Gate Freeway, at the tunnel portals and along the elevated road.

The EES will provide details of the noise assessment undertaken and mitigation strategies to manage noise changes as a result of the project.

The EES will be publicly exhibited in early 2017. After the road is complete, additional noise monitoring will be carried out to ensure that the measures put in place to minimise noise are doing their job.

Construction noise management

Construction companies are required to be considerate in regard to noise and working hours while construction work is underway. We understand that managing construction noise over the construction period is important.

The EES will also assess the proposed construction activities based on the expected plant and equipment to understand noise characteristics during the proposed works.

Where required, measures to mitigate potential construction noise impacts at the identified sensitive receptors will also be included in the EES.

The EES will refer to relevant guidelines, including but not limited to:

Did you know?

Measures used to reduce noise on other similar construction projects include:

  • building temporary noise walls in areas where existing noise walls are being removed, to provide protection until the new, permanent noise walls are built
  • extending construction hours particularly for tunnelling and elevated roads, work hours are managed to minimise disruption to local residents and traffic flow whilst ensuring the safety of workers
  • using noise suppressors on noisy machinery
  • using quieter construction techniqueswhere possible, such as non-disruptive drilling techniques to build bridge piers
  • keeping construction vehicles serviced and fitted with the latest and quietest safety equipment
  • developing a noise management plan, as part of the construction environmental management plan, and undertake construction noise monitoring to verify requirements are being adhered to.

Download the Noise discussion paper (811kb)

Read more

VicRoads Traffic Noise Reduction Policy 2005

EPA Victoria Environmental guidelines for major construction sites (publication 480)

Environmental Protection ACT 1970

VicRoads Noise guidelines – Construction and maintenance 2007

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