In 2020, Phoenix coated 36 miles of roads to fight extreme heat; surfaces became 12°F cooler at noon

In 2020, the city of Phoenix implemented a large-scale project, coating 36 miles of its roads with a special reflective material. This initiative aimed to combat the urban heat island effect, a phenomenon where cities experience higher temperatures than surrounding rural areas.

The treatment proved effective in reducing surface temperatures. Researchers observed that the coated roads were, on average, 12°F cooler at noon compared to conventional asphalt. This cooling effect could potentially mitigate some of the extreme heat experienced in the desert city.

However, the study also highlighted a potential drawback. While the roads themselves became cooler, the reflective surfaces inadvertently increased heat radiation exposure for pedestrians walking nearby. The researchers emphasized that while reflective coatings are a useful tool, they are not a complete solution. They concluded that integrating shade from trees and buildings is crucial for improving human comfort and recommended that cities explore a variety of strategies to address rising temperatures effectively.

“

incorporating shade from trees and buildings is essential for enhancing human comfort, suggesting cities explore a variety of solutions beyond just reflective coatings to address rising temperatures.