This paper on "job sprawl" from Brookings has been getting lots of buzz. The author, Elizabeth Kneebone, used Census data to measure the shift of jobs from central cities to suburbs for the 98 largest metropolitan areas.
She concludes that employment steadily shifted to the suburbs between 1998 and 2006:
Employment steadily decentralized between 1998 and 2006: 95 out of 98 metro areas saw a decrease in the share of jobs located within three miles of downtown. The number of jobs in the top 98 metro areas increased overall during this time period, but the outer-most parts of these metro areas saw employment increase by 17 percent, compared to a gain of less than one percent in the urban core. Southern metro areas were particularly emblematic of the outward shift of job share with a 2.6 percentage-point decline in urban core job share and a 4.8 point gain in the outermost ring, outpacing the 98 metro average (a 2.1 point decline and a 2.6 point gain, respectively).
I've got a few problems were her analysis (and her term "job sprawl"), but I thought the Austin statistics were surprising.
In 2006, the 45 largest metropolitan areas -- those with more than 500,000 jobs -- had an average of 19.6% of their jobs within 3 miles of their CBDs. Austin was well above average: 24.4% of its jobs lay within the "urban core." By contrast, Dallas had 10.6% of its jobs within the urban core, Houston had 11.6% and San Antonio had 14.7%. (Although the San Antonio metropolitan area has 14% more jobs than the Austin metropolitan area, Austin has 45% more jobs in its urban core.)
That isn't really the surprising part, though; Houston and Dallas, at least, are gigantic, sprawling metropolitan areas with several major employment centers each. Austin has three major major employment centers (UT, the State Capitol Complex and downtown) in its core.
What was surprising was the change in urban-core employment. Although the share of Austin's urban-core employment declined from 27.8% to 24.4% between 1998 and 2006, it actually added jobs to its urban core. A lot of jobs. Austin's urban-core added 16,400 jobs between 1998 and 2006, a 12.6% increase. By contrast, Dallas lost 17,683 urban-core jobs (a 6.5% decrease); Houston's urban core lost 19,356 jobs (a 7.8% decrease); and San Antonio's urban core lost 2,655 jobs (a 2.6%) decrease. Thus, of the four large Texas metropolitan areas, Austin was the only one to grow its urban-core job base.
I frequently use Columbus, Ohio as a benchmark for Austin. They both have large universities in their urban cores, and both are state capitals. But Columbus looks a lot more like Dallas or Houston than Austin: Between 1998 and 2006, it lost 19,950 urban-core jobs, an 11.8% decrease. (And its urban-core's share of all jobs dropped from 23.2% to 19.3%).
This is surprising for a couple of reasons. First, Austin's central city-to-suburb transportation network is primitive, bacically just hypercongested MoPac and I-35. Houston and Dallas have much more extensive networks, and Dallas has a rail network. Since transportation costs act like a tariff on central-city employment, I expected to see most growth take place in Austin's 'burbs. Instead, it was the only one of the big four to add jobs to the central city.
Second, I'm surprised to see Austin add so many jobs to its urban core given its relative lack of density. Both Houston and Dallas are denser than Austin using the weighted density metric. While they both have several major job centers scattered throughout the metropolitan area, I did not expect the least dense city add the most central-city jobs.
