Research Team: Dillon Fitch (lead), Susan Handy, and Tatsuya Fukushige
UC Campus(es): UC Davis
Problem Statement: The recent emergence of dock-less electric bike (e-bike) and scooter (e-scooter) shares have a growing number of California cities exploring the use of bike/scooter share systems to improve environmental, social, and health outcomes of the transportation system. Increasing bike/scooter share usage is likely to improve users’ physical activity and reduce their vehicle miles traveled (VMT) and related greenhouse emissions. However, these benefits fall under the assumption that users are replacing a car trip with a bike/scooter trip. If the major mode shift comes from public transit, owned bike, or walking, then the expected benefits of bike/scooter share may be more limited. Many existing studies of bike share systems focus on system dynamics, but less is known about how bike/scooter share influences individual level travel behavior, including substituting for car travel. Considering VMT reduction is a statewide goal for meeting greenhouse gas emissions targets, understanding how bike/scooter share can reduce car travel is important. Additionally, understanding how planning and regulation of bike/scooter share systems influences car substitution rates can help cities craft local plans and regulations to maximize VMT reductions from their bike/scooter shares.
Project Description: The purpose of this study is to examine factors influencing whether bike-share substitutes for driving and the degree to which and under what circumstances bike-share use reduces car travel. Major findings in this report include (1) bike-share in the Sacramento region most commonly substitutes for car and walking trips, (2) each bike in the Sacramento bike-share fleet reduces users’ VMT by an average of approximately 2.8 miles per day, (3) areas with a higher proportion of low-income households tend to use bike-share less, (4) bike-share availability appears to induce new trips to restaurants and shopping and for recreation, (5) bike-share trips from commercial and office areas were more likely to replace walking or transit trips, while bike-share trips from non-commercial areas (and trips to home or restaurants) were more likely to replace car trips, (6) expanding the bike-share service boundary at the same fleet density decreases system efficiency and VMT reductions per bike. The result suggests the need for an efficient rebalancing strategy specific to areas by time of day to increase the service efficiency and its benefits. Further analysis of the data used in this study to examine questions such as how bike share can improve transit connections and factors inducing bike use at the individual level will contribute to the development of more robust models and provide additional insights for bike share operation strategies and policy implementation.
Project Partner(s): Sacramento Area Council of Governments (SACOG), California Air Resource Board, and Caltrans