Eric Jaffe | City Lab

Plans are underway to completely rebuild the Metro Center on Pacific Avenue in downtown Santa Cruz. (Dan Coyro -- Santa Cruz Sentinel)The question of how far people will walk to reach a transit stop has a pretty significant impact on the shape of cities. American urban planners conventionally draw that line at about a half-mile. Some guidelines pull it back to a quarter-mile, while others adjust the distance for bus stops (typically a quarter-mile) and train stations (typically a half-mile), but the consensus holds that no one makes it farther than half a mile that on foot.

The impact of this thinking can be seen clearly in the planning rules a city creates for its transit-oriented development. Take two recent examples: Denver just started a fund to help finance properties built within a half-mile of light rail and a quarter-mile of good bus stops, and the town of Mamaroneck in metro New York just zoned for TOD within a quarter-mile of its commuter rail station. Even as such guidelines encourage urban growth, they also establish a hard edge for it.

New research, set to be presented Monday at the 94th Annual Meeting of the Transportation Research Board, suggests that some cities indeed might be selling their TOD footprint short. A study group led by planning scholar Arthur Nelson of the University of Arizona analyzed the impact that proximity to a light rail station had on office rents in metropolitan Dallas. They found that a quarter of the rent premium (“not a trivial amount,” they submit) extended nearly a mile away from transit. Read more