Job access improves in the face of congestion

Twin Cities study

Jon Boyd, Nov 01, 10.

Access to jobs in the Minneapolis-St. Paul area is improving even as traffic congestion is worsening, according to a report from the University of Minnesota Center for Transportation Studies (via AASHTO). The researchers reported improved access for all modes - including commuting by car. The report (pdf) focuses on the question of access instead of the usual question about mobility:

In this series CTS researchers analyzed, described, mapped, and charted how “accessibility” has changed over recent decades in the Minneapolis-St. Paul metropolitan region. They began by changing the question—from how fast is traffic moving (mobility) to how easily are people reaching places they need or want to go (accessibility).

Asking the accessibility question stands in stark contrast to news accounts about traffic and the way most people talk about transportation. Every year the Texas Transportation Institute (TTI), working on the “mobility” question, publishes its ranking of which metro areas have the worst congestion, and which ones are getting worse faster.

The TTI report gets wide coverage, understandably so, because congestion can damage a schedule (making anyone’s day less efficient), worsen air quality, and certainly be irritating. Congestion also has a “good side”— it signifies a successful region, with a growing number of people going places.

But in this research series, scholars were asking a different question, and they found a different answer: while until this last decade congestion had been steadily worsening, the actual ease of reaching destinations has been getting better—all over the region. And especially by automobile. Accessibility has improved also via walking, biking, and public transit, but the striking findings are the improving access by automobile— and discovering that land-use changes and increased development densities explain most of the
improvement.

Job access in the region improved even though shifting residential patterns did not mirror changes in the distribution of job location, according to the executive summary (pdf):

The single most striking finding: accessibility by automobile, from 1995–2005, increased almost everywhere in the region. The greatest increases in access occurred in the developing edges of the region, in part because there was little real growth at or near
the center where access was already high. And while some new roads were built in this period and others were improved, nothing explains these gains except changes in land use and increased densification in multiple zones of the region.

In 1995 only one traffic analysis zone (near the center) in the entire region could reach more than one million jobs within 20 minutes. By 2005 there were 20 zones with that claim. Well over half the population of the region can reach over one million
jobs within 30 minutes. And if 45 minutes is the standard, almost everyone can reach a million jobs. And these accessibility increases occurred while the center of gravity for employment was shifting— though slightly—toward the south and west of the
region. It increased despite the absence of a matching shift on the part of workers. The labor force tended to shift more toward zones north and south of Minneapolis.

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