Case study of
#00007 Convert dark roofs and pavement to reflective, high-albedo surfaces
Phoenix, Arizona, USA
#00057
Implementer
City of Phoenix Street Transportation Dept & Office of Sustainability, with Arizona State University
Timeline
Since Jan 1, 2020
Location
Description
Phoenix coated 36 miles of residential roadway and a parking lot with a light-gray reflective "CoolSeal" treatment and conducted a multi-year evaluation with Arizona State University — the largest cool-pavement deployment in North America at the time. Surface temperature dropped 10.5–12°F in the afternoon, but daytime mean radiant temperature experienced by pedestrians rose ~5.5°F due to reflected sunlight, and air-temperature gains were small. Los Angeles's parallel Cool Streets program recorded only ~3.5°F neighbourhood air cooling during a heatwave. Researchers recommend limiting cool pavement to parking lots and wide, low-pedestrian streets rather than plazas or playgrounds.
Metrics
5Funding
Lessons learned
- Surface cooling does not equal human comfort: reflective pavement lowered surface and air temperature but raised daytime radiant load on pedestrians, so the street is cooler while people on it can feel hotter.
- Best suited to parking lots and wide, car-centric, low-pedestrian streets; avoid plazas and playgrounds.
- Treat cool pavement as a complement to shade trees, not a substitute — the pedestrian-cooling benefit comes from shade, not albedo.
Sources
3Documented Jun 9, 2026