It may not be well known, but winter tires are different from all-season tires (AKA, confusingly, mud & snow tires). They are formulated with a different rubber formula making them more pliable in cold weather. All season tires are much like a hockey puck. Have you ever been hit by a hockey puck at freezing temperatures? Ouch. I know because that’s what my brother said as he went to the hospital for stitches. Winter tires should be mandated. They provide better traction and can stop faster. I know this because I drive by 4×4 trucks in my compact car because they can’t make it up a hill. Driving all four tires does not work if none of them can get traction. This is a public issue since if someone else does not have them and hits you that might have been avoided if they had winter tires. And, shockingly, when you rent a car they all have all-season tires (same with taxis, buses, etc). This is a safety issue. Winter tires are currently legislated in Quebec if the temperature is below -7C (20F). The city of Calgary is looking at legislating them too.
Update: The CBC Marketplace segment that convinced me to use winter tires. This is also an economic and quality of life issue.