How Your Car’s Color Affects Urban Heat Levels

The color of a vehicle significantly influences the surrounding temperature. Darker cars tend to absorb and emit more heat than brighter ones, especially when parked on the street or in a parking lot. The cumulative effects of countless vehicles in urban areas can substantially intensify the urban heat island effect, exacerbating heat stress for pedestrians on sunny days.

“Have you ever noticed how you feel the heat radiating when passing a parked car on a hot day?” asks Marcia Mattias from the University of Lisbon, Portugal. “It’s not just your imagination!”

Mattias and her team monitored two parked cars (one black and one white) for over five hours under direct sunlight. Their findings revealed that the black car increased local temperatures by up to 3.8°C compared to the surrounding asphalt, which was already at 36°C on a clear summer day. In contrast, the white car had a considerably lesser impact on its environment.

This variation in temperature is primarily due to the reflective properties of vehicle paint; white paint reflects 75-85% of sunlight, whereas black paint reflects only 5-10%, absorbing the majority of incoming light. The thin metal and aluminum bodies of cars heat up rapidly in strong sunlight, unlike dark asphalt, which warms at a much slower rate. “With thousands of cars occupying city spaces, each acts like a small heat source or shield,” Mattias notes. “Their colors can genuinely transform the thermal dynamics of our streets.”

Research indicates that repainting vehicles from dark to light colors can create cooler surfaces on sunny, low-wind days and lower nearby air temperatures. For instance, in the case of Lisbon, performing this change could significantly enhance the sun’s reflection off road surfaces where parked cars occupy over 10% of the area.

Alicia Burke from the University of North Carolina remarked that “utilizing light-colored vehicles as a strategy to mitigate urban heat is particularly innovative.” Previous studies have mainly focused on improving the reflectivity of roofs and pavements.

Government vehicle fleets, taxis, delivery vans, and similar transportation groups are prime candidates for color transformation, according to Mattias.