This. Regulating seasonal snow tire/chain usage in areas with lots of snow/ice is imperative to reducing collisions and improving safety. That and decent infrastructure for clearing snow in a fairly timely manner.

All seasons can't and _wont_ cut it in some areas, and having tires that only work 3/4s of the year for traction is dicey at best.

Source: I drive a Miata in winter up in Saskatchewan

'round these parts (which is hilly and has wet snow), the limiting factor (given decent snow tires) doesn't tend to be traction, it's high centering.