Phoenix Pilots Use Of Cool Pavement To Mitigate Heat Island Effect

Press release from the City of Phoenix:

July 8, 2020

Cool Pavement was applied at Esteban Park in June 2020. This is the first of nine pilot sites selected for treatment. Phoenix Pilots Use of Cool Pavement to Mitigate Heat Island Effect July 8, 2020 12:00 PM.

Something really ‘cool’ is happening in Phoenix…literally! The City of Phoenix Street Transportation Department is launching a pilot study to evaluate cool pavement treatment.

Asphalt collects and retains heat during the day and releases it slowly at night. Phoenix is among several cities that are experiencing the urban ‘heat island’ effect due to the retention of heat within the built environment. US Environmental Protection Agency data shows the difference in nighttime temperatures in heat island areas can be as much as 22 degrees hotter than temperatures measured outside the heat island. Higher nighttime temperatures lead to more energy consumption, more greenhouse gas emissions, air pollution and other harmful effects.

Cool pavement is lighter in color than traditional asphalt or other seal coatings. Cool pavement reflects back the sunlight that hits it. Because the surface reflects, rather than retains heat, cool pavement has the potential to offset rising nighttime temperatures in Phoenix. It should also help cool neighborhood areas that don’t have much shade from the sun.

Cool pavement is not a paint treatment. It is a water-based asphalt sealant that is applied on top of the existing asphalt pavement. It's made with asphalt, water, an emulsifying agent (soap), mineral fillers, polymers and recycled materials. It contains no harmful chemicals and bonds with the asphalt layer underneath.

University researchers will be taking measurements and collecting data over several years to evaluate the results and determine if cool pavement helps mitigate the heat island effect and if those effects are sustainable over time.

Because the Phoenix area climate is unlike other major cities, the study team will also assess how the material holds up against 300 days of sunshine, monsoon storms, high temperatures and daily traffic.

Esteban Park at 32nd Street and Roeser Road was the first site to receive cool pavement treatment. Eight other locations where streets were in good condition but were due for a surface treatment were selected in consultation with the Mayor and Council offices.

To learn more about cool pavement, please phoenix.gov/streets/coolpavement.

This press release was produced by the City of Phoenix. The views expressed here are the author’s own.