Driving in the rain is dangerous for lots of reasons. The roads are slippery, visibility is low, and you may not even realize, but your headlights aren’t doing a very good job illuminating the road in front of you. That’s because most of the light is bouncing off raindrops. But you don’t need to see the raindrops, you need to see what’s beyond them.
That’s why researchers at Carnegie Mellon University’s Robotics Institute have invented a smart headlight system that improves visibility by redirecting light to shine between rain particles.
The headlight system prevents the distracting and sometimes dangerous glare that occurs when headlight beams are reflected by precipitation back toward the driver, which the researchers says can turn a thunderstorm into what looks like a light mist.
The system uses a camera to track the motion of raindrops and snowflakes and then applies an automatic algorithm to predict where those particles will be just a few milliseconds later. The light projection system then adjusts to deactivate light beams that would otherwise illuminate the particles in their predicted positions. Fortunately, the human eye can’t pick up on the headlights’ special flicker.
While it’s a great idea, the system sounds like it isn’t quite ready for primetime: In their tests, the research team demonstrated that their system could detect raindrops, predict their movement and adjust a light projector accordingly in 13 milliseconds. At low speeds, such a system could eliminate 70 to 80 percent of visible rain during a heavy storm, while losing only 5 or 6% of the light from the headlamp, they say.
However, most people aren’t driving at slow speeds. at least not all the time. At 60 miles per hour, the headlights would reduce 15 to 20% of the rain from view. That would still be helpful, but not quite a panacea. To operate at highway speeds and to work effectively in snow and hail, the system’s response will need to be reduced to just a few milliseconds, the researchers said. The lab tests have demonstrated the feasibility of the system, however, and the researchers say they are confident that the speed of the system can be boosted. Eventually, LED lighting combined with image sensors could be entirely operated by a computer chip, reducing the size and cost of the smart headlight system.
The researchers are also working on a way to draw light to road signs or illuminate lines in the road. The projector-style headlight could even harness infrared radiation to detect pedestrians, deer, or other animals moments before the human eye could spot them.
Innovations that target the road are making a difference in human safety. A new analysis conducted by the nonprofit research organization Highway Loss Data Institute found that autonomous breaking and adaptive headlights provide the biggest benefits on the number of crashes each year. It also showed that new braking technology reduced the frequency of property damage liability claims by 14 percent on car models equipped with both forward collision warning and autonomous braking.