Cool Pavement Roads in Sydney, Australia

The City of Sydney Australia is exploring the use of “cool pavements” (i.e., lighter colored pavement) on roads to reduce the urban heat island effect in the city.  The City is evaluating the effectiveness of cool pavements through a demonstration project in which they propose to repave 600 sq. meters of a street in Chippendale, a suburb of Sydney, with lighter colored pavements. Cool pavements are one method of reducing higher temperatures in urban environments because lighter colored pavements absorb less heat energy. The City will install monitoring equipment to assess whether the demonstration project successfully reduces ambient temperatures in the area.  City staff are also researching whether they can reduce the costs of installing cool pavements because these roads, which use a concrete slurry to lighten the color, are currently double the costs of normal roads. The cool pavement project was recommended as part of Sydney’s broader Sustainable Streets and Community Plan adopted by the city’s Environment Committee in March 2013.

Sydney suffers from higher temperatures in the city because of the urban heat island effect.  Cities are warmer than non-urban surroundings because darker surfaces, such as roads and buildings, absorb more heat energy from the sun than lighter colored surfaces – this is the urban heat island effect. As a result of this effect, the Chippendale suburb is 6° C hotter than it would be if it was undeveloped. Cities like Sydney suffer from the heat island effect more because they are filled with more dark surfaces, such as road, paved with dark colored asphalt.  In the Chippendale suburb, darker asphalt roads make up 24% of all surfaces. Climate change and increasing urbanization will exacerbate urban heat islands in Australia, which is expected to see increases in average temperatures. Reducing this heat can alleviate stress, heat stroke, and heat death in urban populations, and it may even result in energy savings for surrounding buildings.

As proposed in the plan, the City repaved a section of Myrtle Street in Chippendale with lighter colored pavements.  To further reduce temperatures the city proposes to increase tree canopy along the road by 80% and painting darker colored roofs in the area with a lighter color.  To measure the effect of the cool pavements and other solutions to combat the urban heat island effect, the City has installed a monitoring system in Chippendale.  These systems send temperature and humidity information to an online server, which allows real-time temperature information to be viewed and downloaded.  To determine the costs and benefits of the program, the City of Sydney has partnered with the University of New South Wales.  The University of New South Wales has developed a report on the costs and benefits which is also available online. As part of its sustainability initiative, the city is recommending increasing its in-road street tree planting by 50% and installing rain gardens.

This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on March 22, 2016.

 

Publication Date: June 2014

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  • Best practice
  • Case study
  • Monitoring

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