Exploring Synergy in Bicycle and Transit Use

With cycling on the rise in many U.S. cities, it is important to consider how other travel modes—especially transit—interact with bicycling. Some transportation experts worry that new bicycle trips substitute more for travel by transit than for travel by automobile; however, bicycling and transit may be more complementary than supplementary. Most research on these connections focuses on multimodal integration: cycling to, on, or from transit. This body of knowledge misses another key component of bicycle—transit synergy: potential long-term complementarity made possible by short-term substitution. A solid transit system provides options and security for bicycle riders to optimize daily mode choices; shifting some peak passenger loads to cycling may make transit service more reliable and entice new users. This study investigated those unexplored synergistic relationships between bicycling and transit use. Exploratory analyses were performed at two scales. First, changes in bicycle commuting in large U.S. urbanized areas between 2000 and 2010 were related to transit levels. Second, logistic regression models used data from a household travel survey in Portland, Oregon, to estimate how transit use affected the odds of cycling by households and individuals and on trips. Results generally supported the research hypotheses: transit and cycling were short-term mode substitutes, but might be long-term complements. Increases in urban area bicycle commuting were positively associated with transit ridership. Although cycling individuals were more likely to live in transit-using households, residing in such a household decreased one's odds of cycling. More research is needed to examine causality and the policy implications of bicycle-transit synergy.