The Cool Road Adelaide project tested three cool road surface products on Bowen Street West in downtown Adelaide, monitoring their effects on reducing surface and ambient air temperature.

Data-based insights

to inform planning

Testing and trialling

climate solutions for resilient cities

Promoting use of outdoor public space

for healthy, engaged and connected communities

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Key findings from the study are:

All three cool road sealants showed a reduced surface temperature when compared to the portion of traditional asphalt road used as a control.
Measuring the impacts of these sealants on air temperature proved challenging and was inconclusive.
Widespread use of the most effective sealant could generate a near 1°C surface cooling at a whole of city scale. While this level of surface temperature cooling across the urban area may not seem substantial it could significantly change the human comfort level and building energy consumption.
Modelling of an increase in tree canopy to cover 33% of roads in Adelaide was predicted to achieve a similar level of surface cooling and would be likely to deliver a higher human comfort due to shading and other benefits of trees.

Understand the impact of the cool road surface on urban heat island effects;
Provide verification of the local benefits of road sealants in mitigating surface temperature;
Work with the CRC for Water Sensitive Cities’ land surface temperature scenario modelling tool to develop an estimate of the day and night time heat island mitigation benefits at a whole of CBD scale.

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Why is this project needed?

Urban heat islands are areas of land that retain more heat than other parts of the landscape. They can be caused where land surfaces like asphalt roads, dark colored pavements and roofs, and artificial turf result in higher surface temperatures.

In Adelaide, roads are one of the hottest land surface types during the day and also retain this heat into the evening. Reducing the build-up of heat on roads can help to encourage their use for cycling, reduce heat loads on cars and properties and contribute to cooler neighbourhoods. While trees offer shade and are often an option for cooling the road surface, they are not always practical in verges and along road sides where there is a narrow carriage way, low hanging powerlines or where there are water, gas, electricity and telecommunications services in the footpath.

How does Cool Road Adelaide address this issue?

A different approach to reducing road surface temperatures is to change the road surface. Climate-KIC Australia, is working to provide evidence to the City of Adelaide and other councils about the efficacy of applying a cool road surface treatment. This involves:

Treating of a section of road with cool road surface paint
Engaging the community to inform about the planned use and purpose of the road surface treatment
Evaluating of the performance of the road surface across a number of aspects
Reporting and sharing of results

The City of Adelaide alongside the South Australian Department of Environment and Water have identified Bowen Street in the Adelaide Central Market District the best location for the trial. This is due to its exposure to the sun, high overnight temperatures, and location as a busy area. Climate-KIC will support coordination between the City of Adelaide and researchers to measure the before state of temperature along the road, prior to installation and conditions that would trigger the installation.