It's really fascinating what happens to snow. They have ploughs that try to clear the sidewalk, but they leave a sizeable layer behind. This layer is packed down by 50,000 people walking on it every day, and the top layer is melted by this friction and refrozen until it turns to ice. And this is what coats the sidewalks here.
I still walk many miles every day, but you know, because I'm such a fatass I need to run or walk at least 10 miles more or more, and so I'll have to run on ice. I really don't care how fantastic your snow boots are, unless you're willing to ship me a free pair of cleats, I'm not going to attempt it.
And you seem to be skirting the idea of me having a heart-attack at 23 years of age. Considering, it seems rather likely.