In theory, Waymo should have a very up to date map of lanes and should be able to very precisely triangulate where it is, so with snow covered road markings it may still do better than humans.
No argument or anything here, just saying what I think is an interesting nuance as someone who has spent a lot of life driving in snowy places.
I’m in Denver now and it’ll be really interesting to see how these things handle the effects of a real storm. If I had to make a guess it would be that they’ll all just stop driving for a day or two.