The Unlikely Technology Helping Autonomous Cars See

When Henry Ford revolutionized transportation a century ago with the mass-produced Model T, it came in just one color: black. Eager to customize vehicles to buyers’ tastes, automakers have since cranked out cars in almost every hue imaginable. Now the industry is again concentrating on its original color to address a dangerous blind spot of self-driving cars: They can’t see black very well.

Dark colors absorb light, which means the navigating lasers of autonomous vehicles don’t quite bounce off—or enable detection of—black cars. Therein lies a potential windfall for old-school companies that make paint. The world’s largest producer of vehicle coatings, PPG Industries Inc., is engineering a paint that allows the near-infrared light emitted by lasers to pass through a dark car’s exterior layer and rebound off a reflective undercoat—making it visible to sensors. PPG got the idea from the purple eggplant, which uses a similar trick on farms to keep cool on hot days.