I expect traction to eventually be one of their strong suits. Machine learning on weather conditions and traffic patterns should work. I’ve got a unique amount of snow-driving experience in most every region of the globe (many years working for a snowboarding magazine) and my hunch is a computer could do this wonderfully. Much of these things should be very predictable with delicate sensory input, and roads have predictable problem spots.

One particularly problematic variable that will undermine weather calculations and traction will be the complications of road de-icer. In high-altitude inland regions, de-icer is not used, with a few exceptions after storms are long gone and the temperature has warmed. These regions should be a piece of cake for autonomous vehicles. Detroit in mid-winter probably resembles this for a few months due to low temps but humidity will destabilize de-icer during early and later winter. And, temp fluctuations resulting from humidity, coupled with high snowfall, necessitates the use of de-icer to prevent the city from getting buried in. In coastal regions like CA, de-icer more predictably melts and cleans the roads. In regions like Chicago, de-icer will hve every effect imaginable, both creating ice and melting it multiple times a day. But if a road is not de-iced the traction will follow a different pattern. I can’t imagine how a self-driving car could determine this. To further complicat things, de-icer can often create ice and be counterintuitive in only shaded parts of the road. De-icer is used so differently, an so often foolishly in different regions.