I grew up in a part of Ontario where total whiteouts can happen fairly frequently on both major highways leading in and out of my small town. It is in fact possible to drive dozens of km in near or total whiteout conditions simply by the hazard lights of the car ahead of you. You very frequently will see lines of cars km long, all going <20km/h, white knuckled and crawling home. Maybe one in every couple thousand goes in the ditch.
I don't think vision-based FSV will ever reliably handle winter conditions like this. The engineering and QA effort just isn't worth the cost-benefit when you factor in the very small amount of drivers who are consistently exposed to conditions like that. My father, who spent his career commuting to the city on that highway, was disappointed when I explained this to him.
I was once in the passenger seat in a downpour. My father was driving to the nav, and it seemed like we were traversing Mekong underwater. It was a complete instrument driving condition, except at most a feet of road markings were visible. The car was on local roads. He made cautious turns and drove slow, because it was obviously scary. Suddenly the nav said "Ding! you have reached your destination" in what seems to be middle of a road, and we immediately started making noises at the nav.
Then a person knocked on a window through the brown wall. It was someone we were to meet at the destination. He greeted us, and told us to come out. We tried to explain we can't just walk all perhaps a quarter mile to the place in this heavy rain, leaving the car left at a roadside. He insisted it'll be a short walk, and gave us no choice. Only when we stepped out, we realized that the car is right in the middle of the premise we were looking for, just couple feet from the main door.
This memory surfaces to my mind in the context of human drivers and inclement weathers; I'm still one piece, but maybe that has more to do with my luck, not necessarily due to myself playing every games extra safe.
The reason all that works is people drive to what they expect. In such conditions you might hit a human standing on the road, no human would be there in the first place, only other cars with flashing lights. As such so long as you stay in the correct lane for your direction of travel and go slow you don't need to see because there is no real danger most of the time. Most of the time...
The worst is when one goes into a ditch and the car following them follows into the ditch because their main indicator of where to go was the running lights and tire tracks of the car in front.
I don't think vision-based FSV will ever reliably handle winter conditions like this. The engineering and QA effort just isn't worth the cost-benefit when you factor in the very small amount of drivers who are consistently exposed to conditions like that. My father, who spent his career commuting to the city on that highway, was disappointed when I explained this to him.