I used to ride on Northern Lights Blvd in Anchorage when the snow-plowing was backlogged. In good winter weather, traffic goes 50mph there. When it's really snowing, traffic usually can't get above 30mph to begin with. When it stopped and the roads turned to ice but there was snow on the shoulder, I'd ride in the right tire track of the right lane. It was obvious that I couldn't be passed without a lane change, so people just changed lanes. Your mileage may vary-- every road is different.

As best I know it, Anchorage law doesn't require cyclists to stay off major non-freeway roads unless there is a usable multi use path as an alternative.