Scientists tested reflective pavement through an Australian summer, and the road surface stayed cooler, but midday radiant heat increased above it

Painting roads a lighter color seems like an easy fix for hot cities, but a yearlong trial in western Sydney shows there is a catch to the fix. According to the Cool Roads Trial, a 2021 study by Western Sydney University researchers Sebastian Pfautsch and Agnieszka Wujeska-Klause, reflective road coatings cooled down the road surface itself, but made the air immediately above the road feel hotter to people standing nearby during daytime hours. The team tracked this trade-off from February 2020 to March 2021, spanning an Australian summer.

A simple coat of paint, a big temperature swing