I received an inspiring paper this evening from U of M's Complex Systems Reading Group: The Complex Interaction of Agents and Environments: An Example in Urban Sprawl (sorry, no link currently available). They use the SWARM modeling environment to simulate urban sprawl dynamics in a "hypothetical" Detroit (accurate statistically in aggregate, but not a replica, I presume). What they find concrete evidence for is Schelling's hypothesis¹ that there can be a disconnect between micro- and macro-behavior, i.e. a group of people each acting individually in their best interests (micro-behavior) can create environments which at a macro level suit the individual's collective interests much less well. We need more of this type of research to assist urban planners in fostering built environments that are more pleasant, more ecologically sound, and more equitable.

[1] Thomas Schelling's Micromotives and Macrobehavior is a classic, published in 1978, and looking primarily at how racial segregation occurs endogenously even in populations with relatively race-neutral views. Recommended!