Self-driving cars sound like a promising innovation – provided road conditions are clear, sunny and well-maintained and you can still find the cheapest insurance. When it comes to snow, rain and other severe weather conditions, the current fleet of autonomous vehicles undergoing testing face many of the same limitations as your average human driver. Ford and Google have implemented tests of their self-driving vehicles in inclement weather to get us all one step closer to a safe, hands-free and worry-free ride.

“Like human drivers, autonomous vehicles sometimes have trouble ‘seeing’ in some low-visibility situations and adapting quickly to loss of traction,” reports Edmunds.com. Self-driving vehicle sensors and cameras can be blocked by snow, ice or blurred by heavy rainstorms – compromising their ability to identify street signs and markings. With 34.47 inches of precipitation averaged across the contiguous United States in 2015, clearly something must be done!

Ford announced at the 2016 Detroit Auto Show that they started conducting the automobile industry’s first autonomous vehicle tests in snow and icy conditions at the Mcity Test Facility, in partnership with the University of Michigan’s Mobility Transformation Center and the Michigan Department of Transportation. “It’s one thing for a car to drive itself in perfect weather,” said Jim McBride, Ford technical leader for autonomous vehicles, in a statement. “It’s quite another to do so when the car’s sensors can’t see the road because it’s covered in snow. Weather isn’t perfect, and that’s why we’re testing autonomous vehicles in wintry conditions – for the roughly 70 percent of U.S. residents who live in snowy regions.” One solution: high-resolution 3-D digital maps to enable the vehicle to recognize road markers and other landmarks to pinpoint its location and identify road conditions based on existing data.

Meanwhile, Google continues to put their self-driving vehicles to the test; Wired reports that they anticipate being “road-ready” by 2020. Google has equipped the sensor domes on top of its self-driving cars with tiny windshield wipers to ensure optimal operations for their LiDAR (light and radar) sensors. Testing their cars on the West Coast and dealing with the recent torrential rainfall has allowed Google cars to enhance their ability in driving under low-visibility and low-traction settings. “For now, if it’s particularly stormy, our cars automatically pull over and wait until conditions improve (and of course, our test drivers are always available to take over),” states Google’s December monthly self-driving car project report.

Self-driving cars might not be fully ready to hit the road this winter – or the next. The forecast: Continued testing to improve or refine these autonomous vehicles brings them closer and closer to becoming a viable reality on roads near you.