Michael Martinez

The Detroit News

One of the big questions surrounding driverless cars is how the vehicle’s sensors and cameras will be able to function in bad weather like snow and ice.

Ford Motor Co. is attempting to solve that problem by testing its fleet of driverless Fusion Hybrids in snowy conditions at MCity, a 32-acre closed-course testing facility in Ann Arbor. Ford will reveal Monday at the Detroit Auto Show that it is using 3-D maps to help the cars safely travel across snow-covered roads.

“It’s one thing for a car to drive itself in perfect weather,” Jim McBride, Ford technical leader for autonomous vehicles, said 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.”

Autonomous vehicles typically use a combination of sensors, cameras, radar, GPS and LiDAR systems to pinpoint the vehicle’s location on the road so the car can drive itself. But what happens when snow covers the car’s cameras and the road signs and lane markers?

Ford says the answer lies in special 3-D maps, developed with the University of Michigan, that allow the vehicle to understand the road’s precise signs, markings and different geography at all times.

“Maps developed by other companies don’t always work in snow-covered landscapes,” Ryan Eustice, associate professor at UM’s College of Engineering, said in a statement. “The maps we created with Ford contain useful information about the 3-D environment around the car, allowing the vehicle to localize even with a blanket of snow covering the ground.”

The cars are able to create the highly detailed maps during good weather and store that information in the vehicle’s memory. Then, when the weather turns rough, the car uses the maps with a combination of traction and electronic stability control to continue driving.

Ford says it hopes to be able to program the driverless cars to sense when conditions are too rough and to stop driving.

Ford first began testing autonomous technology on an F-250 in 2005, and later switched to Fusion Hybrids in 2013. It announced last week at CES in Las Vegas that it would triple its autonomous fleet to about 30 vehicles, which are tested on public roads and proving grounds in California, Arizona and Michigan.

“The reason we picked the Fusion Hybrid is that it has our most advanced electrical system,” Ford President and CEO Mark Fields told The Detroit News last week. “When you think about the processing power you need in an autonomous vehicle, and being able to interact with the radar, sonar and camera systems, that’s why we’re choosing that vehicle.”

The automaker aslo announced it’s expanding its research in smartwatch applications for the car, looking at how it can link health information to driving performance. That way, the car could tell when the driver is sleepy or in need of medical assistance.

“As more consumers embrace smart watches, glasses and fitness bands, we hope to develop future applications that work with those devices to enhance in-car functionality and driver awareness,” said Gary Strumolo, global manager for vehicle design and infotronics, Ford Research and Advanced Engineering.