Accessibility-Oriented Development

Recently published:


Access to jobs and the labor force by car within 30 min.
Access to jobs and the labor force by car within 30 min.

Local authorities worldwide have been pursuing transit-oriented development (TOD) strategies in order to increase transit ridership, curb traffic congestion, and rejuvenate urban neighborhoods. In many cities, however, development of planned sites around transit stations has been close to non-existent, due to, among other reasons, a lack of coordination between transit investments and land use at a broader spatial scale. Furthermore, while TOD considers access to transit, it often neglects the access to destinations that is provided by transit.

We contend that accessibility-oriented development (AOD) can overcome these drawbacks of transit-oriented development. The AOD strategy fosters an environment conducive to development by balancing access to both jobs and workers. As such, AOD explicitly considers the connections between TOD locations and destinations that matter, both locally and regionally. Where markets are free to take advantage of accessibility levels, AOD is a naturally occurring process. Planners could therefore use the various tools at their disposal to influence accessibility levels (to jobs and workers) in order to attract urban development in potential AOD areas.

To test the assumptions that guide AOD strategies, access to jobs and workers are calculated in the Greater Toronto and Hamilton Area, Canada in 2001 and 2011. Cross-sectional and temporal regressions are then performed to analyze average commute times and urban development occurring across the region. Results show that residents in neighborhoods with high access to jobs and low access to competing workers experience the shortest commute times in the region, while the relationship also holds for changes in average commute times between the studied time periods. In addition, both access to jobs and access to workers are associated with changes in residential, commercial and industrial development: high labor force accessibility is associated with increases in job density, and high access to jobs is related to increases in population density between 2001 and 2011. Planners can thus leverage accessibility as a tool to direct development in their cities and to strategically adjust commute times, thereby realizing the full benefits of planned transit investments.

Keywords: Transit-oriented development; Accessibility; Travel behavior; Land use

Study says Blue Line’s development impact is minimal | Star Tribune

Adam Belz in the Star Tribune writes: Study says Blue Line’s development impact is minimal, discussing a recent study by Sarah West and Needham Hurst of Macalester. I get quoted:

“My first sense is the Green Line is a better line,” said David Levinson, a civil engineering professor at the University of Minnesota. “It’s going to a denser area.”

Levinson said that the Green Line — and any subsequent additions to the light rail system — will also improve the value of land along the Blue Line, thus making it more ripe for development as the rail system grows and more people use it.

“That positive feedback system sort of kicks in, and it reinforces the growth,” Levinson said.

Accessibility, Mobility and Density

Are accessibility and mobility complements or substitutes? I have a mental model a graph with a y-axis as density, and x-axis as mobility, where the Northeast corner would be high access: high density multiplied by high mobiilty.
This system behaves differently by modes. For transit, cities arrange themselves on a line from the southwest to the northeast (a positive feedback loop between supply and demand). For auto cities arrange on a line from the southeast to the northwest (a negative feedback loop between congestion and demand). Using data one could place specific cities on the graph. One expects places like New York and Hong Kong in the northeast corner, most US cities in the southeast corner, small developing-world cities without widespread adoption of modern automobile or transit technology in the southwest corner. Depending on where you draw the threshold, it is hard to see too many places in the upper northwest corner, as it would be difficult to grow to have high density without mobility. (Why would the city grow without the accessibility advantages?)
Density Mobility Tradeoff
Accessibility is a good, but it is not a good without costs, and there are limits to how much people are willing to pay for access. It may also suffer from diminishing returns, beyond a point each unit of accessibility is worth less and less. Places like Minneapolis have yet to reach that point, but surely there are places that have.