The report, by Andrew Owen and David Levinson, defines accessibility as “the ease of reaching valued destinations,” in this case jobs. Simply put, it’s an examination of how easy it is for people to get to work.
Each metro region is ranked by how long it takes people to get to work: Jobs that can be reached within 10 minutes are worth more than those accessible with 20 minutes, and so on, up to 60 minutes. Data for job locations is drawn from the Census Bureau, and the time it takes to get there is measured using “detailed pedestrian networks” and full transit schedules for weekdays between 7 and 9 am.
The method accounts for things like how long it takes to walk from a transit stop to a destination and transfer times from one bus or subway line to another. Importantly, it also factors in service frequency and includes the time people spend waiting for a bus or train to arrive…
The authors offer two approaches for improving accessibility. The first is obvious: Offer more and better service that reaches more people. But where jobs and homes are located matters, too. Atlanta has a heavy rail system comparable to those in New York, San Francisco, and Chicago, but because its job centers aren’t as concentrated, that service is less useful, and accessibility suffers. Cities can respond with land-use policies and zoning codes that encourage density around existing transit networks. The height limit on buildings in Washington, D.C., for example, triggers sprawl (away from transit). Oregon’s urban growth boundary laws restrict how much land can be developed, which encourages density. If cities follow the latter example, “encouraging both residents and employers to locate in parts of the city already served by transit,” they can improve accessibility and limit the burden each new residents puts on the transit system.
Given their density, the first two regions in the rankings are not a surprise: New York City and San Francisco. After that, you get a variety of more sprawling cities and regions.
Chicago comes in at number five. Here is the map of the Chicago with redder areas having more jobs accessible by mass transit within 30 minutes.