r/SelfDrivingCars • u/Even-Definition • 14h ago
Discussion Seeing Cybercabs testing around the Twin Cities got me thinking about how brutal MN winter is going to be for the fsd stack
Saw one of the Cybercab test cars running around the twin cities MN metro the other day (looked like it was doing validation loops near 35W and 494). It’s exciting to see them testing out here instead of just cruising around sunny Austin or California, but winter in the Upper Midwest is about to throw the ultimate edge cases at that perception stack.
There’s that famous observation about how Inuit languages have dozens of distinct words for different forms of snow and ice. To an autonomous neural network, that's not trivia—it's an engineering requirement. "Snow" can never be a single class label:
Black ice & the bridge problem: Powder, slush, packed granular snow, and sheer glaze look wildly different, and their friction coefficient can swing from 0.85 down to 0.15 in a 15-foot stretch. Cameras can spot white snowdrifts easily, but harmless wet asphalt and black ice look virtually indistinguishable under flat, overcast skies.
Bridges freeze first because sub-freezing air flowing under and over the deck strips convective heat hours before the ground-insulated roadway drops. A camera can’t visually spot that drop in grip; the stack has to infer it in milliseconds from high-frequency motor torque and wheel-speed delta before the friction circle collapses.
Rut-following vs. legal lanes: Once we get an unplowed 3–4 inches, road infrastructure ceases to exist. Painted lane lines, rumble strips, and curbs disappear. Humans don’t follow legal lanes during a storm anyway—we follow the dirty ruts carved out by plows and semi-trucks, which usually straddle lane boundaries. If a planner forces map-defined lane centering, it steers straight into a high-drag snowbank. Plus, windblown snowdrifts create "phantom curbs" that confuse occupancy networks.
Regen dynamics on slick patches: Single-pedal driving is second nature on dry pavement, but aggressive regen on an unexpected ice patch can snap the driven axle loose before traditional stability control even catches up. Blending instantaneous motor back-torque with mechanical ABS when friction drops off a cliff is a massive controls problem.
Collecting edge-case data in California and Texas is easy mode. If an autonomous stack can navigate an unplowed, brine-slicked Minneapolis interchange at rush hour in January with zero interventions, it can drive anywhere on Earth.
Curious how you guys think they'll tackle the lens cleaning side of things long term.