I think you want an urban planning expert here, to be honest, to answer that.
I'm an energy economist. I can see the benefits when you run your models--what happens to personal kilometres travelled in transportation, what happens to energy burn in buildings. But running good cities, you want good urban planning experts, and there are people who know how to do this. There's been a revolution in this in terms of having multi-use, lots of people, eyes on the street, that kind of thing. But I'm speaking totally from a layperson's perspective.