In the end, what we need to do is not, as Glaeser and Owen suggest, to make everything like Manhattan; It is more likely that we in fact want to make everything like Greenwich Village or Paris, with moderate height buildings that are more resilient when the power goes out. That's the Goldilocks density: dense enough to support vibrant main streets with retail and services for local needs, but not too high that people can't take the stairs in a pinch. Dense enough to support bike and transit infrastructure, but not so dense to need subways and huge underground parking garages. Dense enough to build a sense of community, but not so dense as to have everyone slip into anonymity.
Not too high, not too low, but just right.
I have covered this topic before:
For Saving Energy, Like Real Estate, The Three Most Important Things Are Location, Location and Location
Big Steps In Building: Survival, Not Suburbs
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