Explaining the Limitations of Travel Time Comparisons

Jarrett Walker details the nuances of travel time comparisons, following on a recent Boston Magazine article comparing MBTA transit service to the new Bridj private bus service.

1 minute read

July 2, 2014, 12:00 PM PDT

By James Brasuell @CasualBrasuell


BART Rendering

Eric Fischer / Flickr

Walker finds reasons to fault the "decisive" conclusion of a travel time "race" conducted by Boston Magazine.

"What's really happening here is that a service that is available all the time -- the subway -- is being compared to one that's only available at a few special times -- Bridj's specialized commuter buses.  Any 'travel time race,' with any headstart, is going to miss the real point of this comparison."

There's more in the article, but here's one piece of advice provided by Walker about how to think about travel time: "When I teach transit planning and rhetoric, I encourage people to think of a weighted sense of travel time that includes average wait time, or more generally the difference between when you wanted to go and when you went." 

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