Is Bikesharing Contagious? Modeling Its Effects on System Membership and General Population Cycling

Bikeshare systems are relatively new, highly visible additions to urban transportation systems that provide opportunities to cycle or combine cycling with other modes of transportation. The research reported here presents new evidence about the role of bikeshare systems in travel behavior on the basis of diffusion of innovation theory. The study hypothesized that bikeshare systems have spatial contagion or spillover effects on (a) the propensity of individuals to adopt bikeshare and (b) the propensity to bicycle within the general population. The first hypothesis (H1) was tested by modeling membership growth as a function of system expansion and the existing, proximate membership base. The second hypothesis (H2) was tested by using bikeshare activity levels near home in a model of household-level bicycle participation and trip frequency. The study yielded mixed results. Bikeshare membership growth appeared to be driven in small part by a contagion effect of existing bikeshare members nearby, even after controlling for system growth. However, within the general population, a significant relationship was not identified between proximity to bikeshare stations and cycling participation or frequency. These findings complement those of other recent studies of bikeshare systems, which indicated that systems are still evolving. The present findings also have implications for marketing, infrastructure investments, and future research about bikeshare operations and innovation.