Last year, the City of Phoenix Street Transportation Department and Office of Sustainability teamed up with Arizona State University (ASU) researchers to begin the Cool Pavement Pilot Program, aimed at cooling down neighborhoods and saving energy costs. In a virtual presentation and panel discussion on September 14, the City of Phoenix released the results of the first year of this innovative program. The study, performed by scientists at ASU's Global Institute of Sustainability and Innovation, Healthy Urban Environments, and the Urban Climate Research Center, found that the reflective pavement surface temperatures of CoolSeal by GuardTop are considerably lower than traditional roadway pavement.
In the study, the CoolSeal cool pavement had an average surface temperature 10.5 to 12 degrees Fahrenheit lower than traditional asphalt at noon and during the afternoon hours. ASU Researchers discovered that CoolSeal's cooler pavement coating reflects a higher portion of the sunlight that hits it, absorbing less heat. Thanks to this higher reflection, the coating can potentially offset rising nighttime temperatures in the region.
So far, the study has revealed that the nighttime air temperature at six feet of height was on average 0.5 degrees Fahrenheit lower over cool pavement than on the non-treated surfaces. According to David Sailor, Director of the Urban Climate Research Center at ASU, even one degree can make a big difference.
"A single degree Fahrenheit reduction in air temperature during the summer could save residential ratepayers about $15 million per year in avoided air-conditioning costs," explains Sailor.
The study also revealed that sub-surface temperatures averaged 4.8 degrees Fahrenheit lower in areas treated with CoolSeal. According to Davis Koleas, GuardTop's Sustainability Project Manager, this means that the depth of the asphalt was almost five degrees cooler, not just the surface, which shows that the asphalt is staying softer and not hardening or cracking. This is great news for municipalities, since it proves that CoolSeal is lasting longer, which will reduce future maintenance costs.
Ultimately, reducing surface temperatures can result in cooler air temperatures, which, as Sailor points out, can have significant implications for heat-related illness, air quality, water use, and energy use.
City staff is developing plans for a second phase of the Cool Pavement Pilot Program.
"The effects of urban heat islands can be felt by everyone, and greatly impact our ecosystem and day-to-day life," says Koleas. "Phoenix and ASU both invested time and money into effectively working to reduce the harm that has already been caused. We are confident residents and visitors alike will reap the benefits and find increased comfort all around."
With this pilot program, Phoenix now has the most cool pavement in North America. Los Angeles, California is following in its footsteps, with Mayor Eric Garcetti recently kicking off the next phase of his ?Cool Streets L.A.' program, which will bring 200 blocks (or more than 60 miles) of cool pavement and nearly 2,000 new trees to eight neighborhoods across Los Angeles.
About GuardTop, LLC
Since 1983, GuardTop has been committed to providing superior asphalt-protection products. With an ever-growing product line and commitment to sustainability, GuardTop has become an internationally-trusted asphalt-based sealcoat manufacturer. A family-owned company with strong values rooted in safety and environmental compliance, GuardTop goes the extra mile to ensure all customers and employees are treated like family.
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