Yesterday, I drove from my in-laws’ house in Sacramento, up into the mountains to go cross-country skiing near Lake Tahoe. It was a lot of fun! The snow was surprisingly good for November.
The drive down was a spectacle, though. Snow was starting to come down and the Interstate highway leading down from the mountains turned into a parking lot. Cars got stuck and stopped in the middle of the highway to put on snow chains. It became impossible to see where the lane lines were.
This got me thinking about what a mess driving in the snow can be, and all the more so for self-driving cars. Sensors like cameras and lidar can become mostly useless in the snow, which completely changes the physical surface of the road.
One solution to this problem is a research project out of MIT: ground-penetrating radar.
This technique uses VHF radar to scan through the surface of the road and down to subterranean elements. Supposedly, similar techniques are used by archeaologists.
Obviously, the below-ground composition of the earth doesn’t change with the weather. So if a vehicle can map the ground underneath the road once, then it can come back later and figure out where it is, even in a blinding snowstorm.
Pretty cool stuff.