It’s also a lot worse to drive on when it’s near freezing. Snow with a bit of water in it can be way slippier than even slush, and almost as bad as ice. Near freezing is also the conditions that can leave you with black ice in the mornings or late evenings if the snow melts enough during the day, or where ever else the water’s coming from.

Mix in the fact that people in regions where it snows rarely royally suck at driving in adverse conditions, and it kinda’ actually makes sense even beyond not having plows for cities to more readily shut down over snow in such areas.