By Patrick Appel
Jonathan Zasloff wants more communal lawns:

You can easily have single-family neighborhoods with greatly increased density, and the walkability and transit accessibility that comes from that, if you reduce lawn size and share some of that open space. No, this isn't an apartment building: all the kids (animals?) live in single-family, detached homes. [...]

So why don't more neighborhoods have this? Because in most suburbs, it's illegal: you can't share a lawnthere are setback requirements, fencing requirements, lot size requirements, etc. Developers won't build what they can't entitle. And so we assume that single-family neighborhoods mean far lower density, and transit accessibility, than we should.

Bradford Plumer adds his two cents.