According to AAA, car safety systems don't always "see" in bad weather.
Advanced driver assistance systems (ADAS) have erupted onto the market over the past five years or so. Autonomous emergency braking and lane keeping assistance are just a couple of the high-tech safety features that are sometimes standard on even entry-level car models. These systems are not autopilot; they cannot, under any circumstances, drive for you. However, they greatly improve visibility and reaction times. However, if something, such as mud or snow, is obstructing the systems' cameras, they are unable to accomplish their jobs. Today's modern automobiles combine optical cameras located behind the windscreen with radar sensors that are concealed behind plastic in the bumpers. Weather and sunlight don't actually effect radar much, and since these sensors are concealed by plastic, bugs don't really trouble them either.
But lane markers and other elements are invisible to radar. The cameras are used in this situation. Cameras are better at categorizing objects, but they struggle to "see" in poor lighting or weather conditions. With the assistance of the Automobile Club of Southern California's Automotive Research Center, AAA tested the automatic emergency braking and lane keeping assistance systems' camera performance in a simulated moderate to heavy downpour.
The four typical SUVs they evaluated used a combination of radar sensors in the bumpers and optical cameras located behind the windshield, just like the majority of modern automobiles. The water simply needed to be splashed over the windshields to test the cameras because rain doesn't actually influence radar. It's important to note that the track was dry, which gave the tires the most traction. At two low, neighborhood-appropriate speeds, researchers evaluated the automated emergency braking systems of vehicles and discovered that at 25 mph, 17% of the test runs terminated in crashes. 33 percent of the test runs ended in crashes when the speed was raised to 35 mph.
The radar sensors nevertheless performed their duties as effectively as they could without the camera's "eyes," but it wasn't ideal. The lane maintaining assistance feature had much more difficulty. 69 percent of the time, test vehicles veered off the road. Lane markers are invisible to radar, as is also true of cameras trying to see through heavy rain. According to the whole study we reviewed, testers also imitated windshields by stamping the glass with "a concentrated solution of bugs and filth." Ew. It's interesting that this small amount of filth on the glass had no detrimental effects on the cameras. However, your expensive ADAS won't be able to see very effectively if your windshield is dirty. At least get rid of the insects.
Previous study by AAA has demonstrated that these systems are insufficient. High traffic and curved lanes can hinder a car's ability to follow a specified lane, and ADAS doesn't always detect nighttime pedestrians. All of this study indicates that while your car's ADAS can help you, it cannot yet take your place. Still the best onboard computers are our own brains.