Autonomous vehicles need to operate in a complex environment, and recognizing traffic signs is an important part of that. A new microstructured material reflects light in rainbow rings, which can make traffic signs easier for computer vision systems to read.

Even outside of fully autonomous vehicles, traffic sign recognition has been part of driver assistance systems for over a decade. Normally the technology is based on recognizing colors or shapes of signs, but it doesn’t always get it right in the real world, where readability can be affected by lighting, weather, obstacles, damage, or something as simple as stickers on the sign.

So for the new study a team of researchers investigated a promising new material that could make the job easier. It’s a new form of retroreflective material, already commonly used to highlight signs and road markings by bouncing light from a vehicle’s headlights straight back at a driver. But rather than focus that light, the new material scatters it to create eye-catching patterns.