Trees, traffic, and air pollution shape perceptions of waiting time

Bus driving surrounded by treesFor transit riders, waiting times seem longer at stops with heavy traffic and high levels of pollution. However, if dense, mature trees are nearby, waiting times seem shorter. 

These are some of the findings from an analysis by U of M researchers. The analysis stems from data collected for a previous study led by Associate Professor Yingling Fan of the Humphrey School of Public Affairs. That effort studied how amenities provided at stops—such as shelters and information kiosks—affect waiting-time perception. (See related article about a video discussing this research.)

The related analysis compared transit users’ actual and estimated wait time at 36 stops and stations in a mix of environments in the Twin Cities region. For waits longer than 5 minutes, perceptible pollution and exposure to traffic led to significant overestimates of waiting time. Riders waiting at stops with dense, mature tree cover, however, significantly underestimated their waiting times. In fact, the effect of dense, mature tree cover was strong enough to compensate for the effects of both air pollution and traffic awareness.

The analysis was performed by a team that included Fan, Marina Lagune-Reutler (graduate student), and Andrew Guthrie (research fellow) of the Humphrey School, and David Levinson (former professor, Department of Civil, Environmental, and Geo- Engineering). Results are published in the Transportation Research Record: Journal of the Transportation Research Board (No. 2543).

Another paper co-authored by Fan looks at waiting-time perceptions at bus and metro stations in Nanjing, China. Similar to the Twin Cities results, the study found that waiting at metro (rail) stations or bus stations with high-quality amenities seemed to shorten the perceived waiting time. Findings are in Transportation Letters: The International Journal of Transportation Research (published online Nov. 2, 2017).

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