20-Minute Neighborhoods
So, I like this, and enjoy neighborhoods (usually in old inner cities) which approach this, but one thing I don't see often acknowledged, is the difficulties of homelessness for this concept.  People often don't like to say it out loud, but one of the principal drivers of the urge to retreat inside your car, is the fact that it puts a barrier between you and the crazy guy shouting on the streetcorner.  We have not yet found a system that effectively removes the angry shouting, or urinating, or otherwise crazy-acting person from the sidewalk, or bus, or urban train, that is not uncomfortably close to a police state.<p>Not saying it cannot be done, I'm sure it can, but I haven't seen it.  One of the principal obstacles to any pilot plan of this sort, is that it is a magnet to those people who don't get social interaction any other way (because few people wish to be around them), so it is at risk of being descended on.  Plus, some people (the sort who otherwise are quite in favor of public transport in the abstract) don't want to be thick-skinned enough to deal with even one such person.<p>Me, I'm kind of a jerk, so I don't mind; it's all part of the human experience.  I have the ability to tell such a person that I'm not talking to them today (unless I am), without being wracked with guilt for the rest of the week.  But a lot of people (who otherwise would be in favor of this idea) just cannot (or do not wish to) be thick-skinned enough to cope with this.