Jaffe's article focuses on a study by Elliot Martin and Susan Shaheen, first mentioned in an article by Gabe Klein earlier this month. The study, "Evaluating public transit modal shift dynamics in response to bikesharing: a tale of two U.S. cities," evaluates survey data from Washington D.C. and Minneapolis "to explore who is shifting toward and away from public transit as a result of bikesharing," as described by the study's abstract.
According to Jaffe's summation, "the maps suggest that bike-share, at least in Minneapolis and Washington, is making the entire multimodal transit network more efficient. For short trips in dense settings, bike-share just makes more sense than waiting for the subway—it's 'substitutive of public transit,' in the words of Martin and Shaheen.
Where Klein took the findings of the study as evidence that cities should rethink transit-oriented development around multi-modal facilities such as bikeshare, Jaffe suggests that we should expand our definition of public transit to include publically funded bikeshare.
According to Jaffe's argument, "with increasing evidence that bike-share can expand or support public transit networks, the case for improving these systems with taxpayer dollars becomes much stronger."