Quick note to call attention to this article in the New York Times: Car-Free In America?
Interesting that those are the exact cities (minus Philadelphia, plus Montreal and Toronto) that formed my idea of what a city is. All mass transit towns. Everything else still seems exceptional and sub-urban in the sense where “sub” means “worse than”.
There are only six American downtown districts that are dense enough to support mass transit, which you need if you’re going to be carless: New York City (Midtown and Downtown), Chicago, Philadelphia, Boston and San Francisco.