Everyone, and I mean everyone, is linking to this Brookings report on “job sprawl,” or the change in employment concentration, which updates previous numbers. From 1998 to 2006, as it happens, the percentage of jobs within 3 miles of central business districts fell, while the percentage of jobs more than 10 miles from central business districts fell rose. Given the vagaries of urban structures, it’s easy to read too much into this report. Las Vegas, for instance, is considered heavily concentrated, because there are few jobs beyond 10 miles away from the CBD, because beyond 10 miles away is desert. That doesn’t really mean that Vegas is any kind of planner’s paradise, however.
And in Washington, the share of jobs near the CBD fell, but the absolute number of workers within 3 miles of the CBD rose by over 40,000. What’s more, the area within 10 miles of the CBD contained over half of the area’s jobs, despite having a much smaller land area than the outskirts. Of course, this portion of the metropolitan area is getting much dense, with inner suburbs looking over more like the CBD.
In other words, the degree of centralization is important for some metrics, but just as important is how closely people live to their places of employment, how they move between the two, and what the land-use paradigm is. A far-flung metropolis with dense residential-commercial clusters around transit nodes is in many ways preferable to a much smaller city where all uses are kept separate and everyone has to drive everywhere.
One other thing to consider — the period in question corresponds with the housing bubble, which suggests that some of this shift may be unsustainable. Over 50% of construction jobs were outside of 10 miles from the CBD, but most of those jobs are now gone, and much of what they were building is now empty. So we’ll see how this looks in eight years.