Low-density suburbs good for integration

Could Suburban Sprawl be Good for Integration?

Low-Density Neighborhoods More Likely to Stay Integrated

Duke Today, September 23, 2014

DURHAM, NC - Racially and economically mixed cities are more likely to stay integrated if the density of households stays low, finds a new analysis of a now-famous model of segregation.

By simulating the movement of families between neighborhoods in a virtual “city,” Duke University mathematician Rick Durrett and graduate student Yuan Zhang find that cities are more likely to become segregated along racial, ethnic or other lines when the proportion of occupied sites rises above a certain critical threshold -- as low as 25 percent, regardless of the identity of the people moving in.

Their results appear online in Proceedings of the National Academy of Sciences and will be published in a forthcoming issue.

Using sophisticated computer simulation to replace Schelling's physical model, Durrett and Zhang modeled the behavior of two kinds of families, designated as blue and red, as they moved from one part of a city to the next in search of a neighborhood they consider “acceptable.” 

By analyzing the model, the Duke researchers showed that reds and blues can happily coexist indefinitely as long as the density of occupied sites in each neighborhood remains low.

However, as soon as the density of households in a neighborhood exceeds a certain threshold -– in this case 25 percent of the available sites, regardless of color –- the city quickly becomes segregated. Before long, the reds start to cluster in red neighborhoods and the blues in blues, until eventually the majority of families live in neighborhoods where almost all of their neighbors look like them.