Until I see autonomous vehicles testing in blizzard conditions, or even a moderate snowfall, it's relegated to the West coast. This eliminates nearly 2/3 of the US population (who live in areas where snowfall occurs).
We're at least 5-7 years away from them testing in these conditions.
That 'testing' is taking place on the University of Michigan's M City track. I'm looking forward to testing during these conditions, in the real world, with someone behind the wheel acting as backup.
I'll revise my 5-7 year comment then - I think it will this amount of time (if not more) for these autonomous vehicles to move beyond testing (prod) in winter climates.
Driving on the interstate in a snow storm with semi trucks is no joke - there might actually be a threshold in which pulling over is the best option.
We're at least 5-7 years away from them testing in these conditions.