AAA study finds vehicle safety systems are negatively impacted by rain

Researchers from AAA have published a new study looking at how moderate to heavy rain affects the ability of modern vehicle safety systems to function. AAA conducted testing in a closed course environment simulating rainfall and discovered that test vehicles equipped with automatic emergency braking they were traveling at 35 mph collided with stopped vehicles 33 percent of the time during rain. Other vehicle safety features were also impacted during rain.

Other tested features include lane keeping assist, which allowed the vehicle to depart their lane 69 percent of the time during grade. AAA says that vehicle safety systems called advanced driver assistance systems are typically tested in ideal conditions. AAA believes testing standards need to be changed to incorporate real-world conditions that drivers would typically encounter.

Safety systems rely on cameras and sensors to visualize markings on the road, cars, pedestrians, and other obstacles. AAA's Greg Brannon says people don't always drive around in perfect sunny weather and test methods need to be changed to take real-world conditions into account. AAA says its research found rain had the biggest effect on vehicle safety systems.

However, they also stimulated other environmental conditions, including bug impacts and dirt. The results found that driving in simulated moderate to heavy rain impacted both safety systems. Automatic emergency braking engaged while approaching a stopped vehicle in the lane ahead at 25 mph but resulted in collision 17 percent of the time.

When speeds were increased to 35 mph, collisions occurred 33 percent of the time. Overall, during testing, lane keeping assist veered outside of lane markers 69 percent of the time. Researchers said that when testing systems with a simulated dirty window stamped with a concentration of bugs, dirt, and water, only minor differences in performance were noted. However, cameras can be influenced by a dirty windshield, and AAA says it's important that drivers keep the windshield clean.