Washington, D.C., Tests Light-Colored Roads to Cool Streets During Extreme Heat

When temperatures rise, pavement can trap heat and make city streets feel even hotter. Washington, D.C., is testing a new approach by changing the color of some roads.

The District Department of Transportation has launched a "Cool Corridors" pilot program aimed at reducing temperatures in areas designated as urban heat islands.

These areas typically have fewer trees and large amounts of pavement. On hot days, dark asphalt absorbs sunlight and releases that heat back into the surrounding environment.

As part of the pilot program, crews are applying light-colored, reflective materials to roads in five areas across Washington, D.C.

DDOT Director Sharon Kershbaum said the relatively simple change could have a significant impact.

"By putting on a lighter coating, we can reduce the temperatures by about 20 degrees," Kershbaum said.

The reflective material is designed to bounce sunlight away rather than allowing dark asphalt to absorb it, potentially lowering temperatures across surrounding neighborhoods.

Officials are testing three different types of pavement coatings to determine which performs best. They will also study how well the materials withstand Washington's winter conditions, including snow and road salt.

Strategic Project Engineer Nepolina Chhetri said most previous studies on cool pavement have been conducted in areas with consistently hot climates.

Washington's four-season climate provides an opportunity to study how reflective pavement performs when exposed to both extreme heat and winter weather.

DDOT is working with American University to compare data from the treated roads with nearby streets that have not been painted.

Officials hope the results will identify the most effective and durable coating. If the pilot program shows measurable benefits, the district could expand the technology to additional streets.

Megan McGrath reporting.