I should clarify...
Chains only required for 2-wheel drive vehicles without H rated tires or whatever they are (i.e. Blizzacks). And only required when it's a shit show out and the roads are covered, icy, and you're plowing through the ruts. It can still be rutted out without having bare asphalt. Precisely the conditions mulitple times last year that took people 6-8hrs to get back to Denver, not every time it snows a little or every time there's a chain restriction for commercial vehicles.