Estimating the effect of protected bike lanes on bike-share ridership in Boston: A case study on Commonwealth Avenue

Abstract

While many studies have studied the connection between cyclist ridership and the built environment, few findings provide relevant quantitative guidance to decision-makers. This study examines the effect of a single intervention (installation of a protected bike lane) in Boston, Massachusetts, on the nearby ridership of 'BlueBikes', a local bicycle sharing system (bikeshare). Bikeshare activity along the new protected bike lane almost tripled in the year following installation; however, ridership on routes unaffected by the new bike lane also saw dramatic increases in ridership. Using a differences-in-differences comparison, which assumes the bike lane had no influence on adjacent routes, suggests that the causal impact of the new bike lane increased bikeshare ridership +80% on affected routes. These quantitative estimates represent credible upper and lower bounds on the effect of replacing a conventional bike lane with a protected bike lane. Additional analysis also suggests that the influence of the bike lane is strongest when trip origins and destinations are a minimal distance (under 1.6 km) away from the bike lane, which may be useful information in planning bicycle networks.