Other exception: really cold cities. See the Calgary +15: http://en.wikipedia.org/wiki/%2B15 http://en.wikipedia.org/wiki/%2B15 They get around the foot-traff

Other exception: really cold cities. See the Calgary +15: http://en.wikipedia.org/wiki/%2B15 http://en.wikipedia.org/wiki/%2B15 They get around the foot-traffic problem by basically bringing the commerce up as well- it's like a giant indoor mall on the second floor of interconnected buildings.