Coomera Connector Stage 1—Road traffic noise
The Department of Transport and Main Roads follows the Transport Noise Management Code of Practice (Volume 1, November 2013) to minimise road traffic noise impacts, ensuring compliance with the Environmental Protection Act 1994. This code guides the assessment, design, and management of road traffic noise, determining where noise treatments are required.
A detailed road traffic noise assessment for Coomera Connector Stage 1 has been completed to ensure noise is managed appropriately into the future.
Noise monitoring
Initial noise monitoring was conducted by external acoustic engineers between July and September 2020 at properties along the corridor considered to be representative of those properties most exposed to traffic noise. This monitoring has established baseline noise levels.
Additional monitoring to gather further baseline noise levels may be conducted by the design contractor for each construction package.
Post -construction noise monitoring will be carried out at the same or similar locations to where previous noise monitoring was completed.
This post-construction noise monitoring will help to verify the noise modelling and confirm that any noise reduction measures installed as part of the project have performed appropriately.
Noise modelling
As part of finalising the design, predicted noise levels are modelled and assessed against baseline noise levels taken from actual noise monitoring data obtained from various locations throughout Stage 1 of the project.
To determine where noise treatments are required, the noise modelling includes such things as the road alignment, ground topography, road gradients and pavement surfaces, predicted traffic volumes, types of vehicles and vehicle speeds.
Noise barriers
Noise barriers, ranging from 4–6m in height, will be installed where needed. Some may include acrylic panels for natural lighting.
The contractors will notify affected residents once details are finalised.
In-house treatments
Our preference for treatment is to install noise barriers as this provides maximum noise reduction benefits to a wider number of properties so represents best value for money. Sometimes installing a noise barrier is not possible due to inconsistent terrain levels or when only one property in the catchment is predicted to exceed the criterion because it has upper level living areas.
In these cases, we may instead propose in-house treatments such as mechanical ventilation, air conditioning or double-glazing to windows. When considering exceptional noise treatments such as window glazing and air conditioning we refer to Section 3.3 of the Transport Noise Management Code of Practice, Criteria for Exceptional Circumstances Treatment.
If any properties along the alignment require Exceptional Circumstances Treatments, we will contact those landowners once post-construction noise monitoring is completed.
Road surface
Concrete road surfaces are no longer routinely used for state-controlled roads in urbanised areas of Queensland.
Today, there are newer road pavements that can be considered, including open graded asphalt, which is the quietest road surface currently available for use in Queensland. The road surface of the Coomera Connector will be open graded asphalt.
Vehicle noise
Intermittent noise from truck engine breaking, motorbikes, modified vehicles, and emergency sirens cannot be mitigated by noise barriers. Engine braking, a critical safety mechanism, cannot be prohibited and signs requesting drivers to limit engine braking are not legally enforceable. We have found that these signs do not have a measurable effect in limiting engine braking noise in the immediate vicinity and so will not be installing such signage as part of the Coomera Connector project.
Construction noise
The department is mindful of the impacts of construction noise on residents and does everything reasonably practicable to minimise noisy works. The department and its contractors will keep residents up-to-date and informed of noisy works. Advanced notice will be provided via flyers, face-to-face meetings, and email.
For more information about construction noise, refer to the Construction noise and vibration page.