It gets real hard when the entire road surface is covered with snow for weeks at a time (like after small 1" snowfalls that might not get cleared immediately li

It gets real hard when the entire road surface is covered with snow for weeks at a time (like after small 1" snowfalls that might not get cleared immediately like a heavy snow would). Or when snow buildup on the road edges change road edge location and cars parked on the side project well into the "nominal" GPS derived lanes. Lanes which human drivers won't be using. They'll be using emergent lanes defined by flocking behavior. I haven't seen any evidence that autonomous vehicles can detect or navigate such emergent, non-marked except by tracks and human gut feeling lanes. Being "better" than human in these situations will cause crashes. The real goal is to drive like a human.