Researchers Described How A Car’s Colour Influences The City’s Temperature

The colour of the vehicle can directly affect the temperature of the air around it. Dark cars heat the air around them, raising temperatures in cities. Bright cars reflect sunlight, offering a simple way to cool streets, a new study has found.

“When you pass a parked car on a hot day and you feel the heat radiating—it’s real, it’s not your imagination,” Marcia Mathias of the University of Lisbon told New Scientist.

Marcia Matias and her team followed two cars, a black and a white one, left outside for more than five hours under clear skies while the air temperature was 36 degrees Celsius. The black car increased the temperature of the nearby air by as much as 3.8 degrees compared to the asphalt, while the white car did not cause any significant change.

Why does colour matter?

White reflects 75–85 percent of sunlight, while black reflects only 5–10 percent. A car’s thin steel or aluminium body heats up faster than thicker asphalt, amplifying local heating.

“Now imagine thousands of cars parked around the city, each one acting as a small heat source or heat shield. Their colour can actually change the temperature on the streets,” explains Marcia Mathias, one of the authors of the study published in the journal “City and Environment Interactions.”

As stated, repainting dark cars in lighter shades could increase the reflectivity of surfaces from 20 to almost 40 percent in areas where parked cars occupy more than 10 percent of the roadway.

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