Some suburban items to share today:

Design: Infrastructurist takes a look at the problem of culs-de-sac (which I believe is the proper plural of cul de sac).

Commenters take note of some serious issues with this particular study, but the general point still stands – culs de sac remove key links from the street network, requiring longer and more circuitous routes to get to the same destinations.  Developments of these kind of street patterns are no small part of America’s long history of vehicle miles traveled increasing far faster than the rate of population growth.

Diversity: The Washington Post has an article on the changing face of suburbia – more socially and economically diverse, and dealing with new sets of problems that many of these communities have never had to deal with before:

Demographers at Brookings say suburbs are developing many of the same problems and attractions that are more typically associated with cities. And cities, in turn, have been drawing more residents who are young and affluent, so the traditional income gap between wealthier suburbs and more diverse cities narrowed slightly.

“The decade brought many cities and suburbs still closer together along a series of social, demographic and economic dimensions,” said the report, titled “State of Metropolitan America.”

The other substantive point is about how Americans perceive their surroundings (urban, suburban, rural) compared to how their city and their urban economy actually functions:

The report outlines a decade in which several demographic milestones were passed as the nation’s population topped 300 million midway through. About two-thirds of Americans live in the nation’s 100 largest metropolitan areas, virtually all regions with populations of 500,000 or more.

“We think we’re a small-town nation,” Berube said. “But small towns exist because they’re connected to something bigger, which allows residents to make a living.”

Density: Ryan Avent has long marked the economic benefits of density and the nature of urban agglomerations, but he has an interesting point on the marginal benefits of added density, noting that modest increases in the less dense suburbs could have a troubling impact, while modest increases in the already dense core, already designed at a walkable scale, would have serious benefits for local retail.

So let’s think about the effects of doubling density in Fairfax and the District. Now on the one hand, the benefits to doubling density in Fairfax are likely to be larger than those in Washington for reasons of scale alone — in the Fairfax example, more people are added. That makes for a deeper labour pool, a larger skills base, and so on. On the other hand, Fairfax density is likely to be less effective density. Fairfax is built in a fairly standard, suburban way. It’s not built at a walkable scale, the road system is arterial rather than gridded, transit options are limited, and so on. Doubling density, absent major infrastructure improvements, might actually reduce the metropolitan access of Fairfax residents.

Not so in the District. Yes, with more people roads, buses, and the Metro would be more heavily taxed. At the same time, every neighborhood would become individually more convenient. Brookland is fairly low density for a District neighborhood, but it’s basically built to be walkable. Were density in Brookland to double, the retail and commercial options within easy walking distance of Brookland residents would more than double.

The problem with doubling the density in a place like Fairfax County, aside from the infrastructure issues that Ryan highlights, is that you’d end up with a place that’s stuck in the no-man’s land of density – too dense for the auto-oriented infrastructure to function smoothly, but not dense enough to really tap into the critical mass and benefits of walkable urban places.