Bikeshares Are Not an Alternative to Public Transit

Public bikeshare systems (PBS) have become increasingly popular in cities, prompting studies on their relationship with different forms of transit, including cars, rideshare, walking, and public transit such as buses and rail. Many of these studies have found that PBS reduces the use of all other modes of transit (Bullock, Breeton, and Bailey, 2017; Fishman et al., 2014a). However, the shift has not solely been from the former modes of transit to bikeshare. PBS provides opportunities for different modes of transit to complement each other and reduces the amount of transfers a commuter may need to make.

Bike share programs began in the 1960s in Europe but failed to gain popularity due to vandalism and theft. Later developments resolved these issues, requiring a deposit to access the bikes and implementing a docking system to centralize their location. Bikeshare has become increasingly popular in cities and continues to develop today with dockless systems. This has left cities asking, how is the rise in popularity of bikeshare systems influencing the future of public transit?

Surveys conducted on the relationship between bike sharing and public transit have determined that bike sharing influences commuters’ choice in transit. Previous studies have also found that many users of bikeshare also use public transit during their commute. The substitution of bikeshare for public transit has been studied more than the integration of the two modes of transit and Kong, Jin, and Sui attempt to fill in these gaps with their study, “Deciphering the Relationship Between Bikesharing and Public Transit.”

While bike sharing competes with other modes of public transit such as buses and rail, it can also complement them by filling transportation gaps to underserved areas. Unlike many of the previous studies conducted on PBS that survey users, the authors use data they obtained on bike sharing use, public transit timetables, and demographic data from some of the largest cities that use PBS: Boston, Chicago, Washington, D.C., and New York City. By using comprehensive bikeshare data, the authors were able to quantify the effects and identify spatial patterns of those who use bikeshare programs. To facilitate comparison, they selected a weekday and weekend from each city that had similar weather and event patterns (no major events). PBS data was collected from the operators’ official websites, public transit data from the General Transit Feed Specification, and demographic data from the American Community Survey for 2013 to 2017.

The authors grouped bike share trips into three categories: modal substitution (MS), or a trip used to replace public transit, modal integration (MI), or a trip used to connect to public transit, and modal complementation (MC), or a trip in an area underserved by public transit. First, the authors conducted an analysis to determine whether a bikeshare trip area is covered by public transit or close enough to make a connection. They also considered public transit schedules, including whether the ride would have ended in a reasonable timeframe to make a transfer. Next, they conducted a trip duration analysis, finding that riders who use bikeshare typically make a transfer after trips of two miles or fewer. Finally, they conducted a transfer analysis for transit trips longer than two miles. If one or no transfers were needed on longer trips, they would be considered substitutions to public transit. If two or more transfers are needed it would be considered modal complementation.

Separating their data analysis into weekdays and weekends, the authors found that a majority of weekday bikeshare trips are MI trips (trips where bikeshare is used to connect to public transit) and a majority of weekend trips are MS trips (trips where bikeshare is used to replace public transit). They also found that different types of riders took different types of trips. Subscribers, who are usually residents that use bikeshare for commuting and have a monthly or multi-day pass, took a majority of the trips completed on weekdays. Customers, who are typically visitors using bikeshare for leisure, took a majority of trips on the weekends in all cities but Washington, D.C. Overall, customers make more substitution trips and subscribers make more integration trips. Additionally, during late night and early morning when public transit is limited, there is an increase in complementation trips due to a lack of access to public transit.

While these data are helpful for filling in the gaps of research around PBS and offer an approach that uses data instead of surveys, further research is necessary. Kong, Jin, and Sui do not consider trips less than two miles where bikeshare is used as the only mode of transportation. Trips where riders only used bikeshare could have been falsely represented as examples of modal integration. However, the potential for overestimation of integrated trips may be balanced out by the use of strict thresholds in the analysis, including limiting integrated trip distance on a bikeshare to under two miles and only accounting for transfers that could occur within 10 mins based on public transit schedules. Additionally, this study only looks at large cities with large public-transit systems that have relatively high coverage. PBS patterns may be different for smaller cities without a developed public transit system. The lack of survey data also obscures the intention of these trips — not all transfers may have been detected. Not knowing where bike share riders live also limits the full picture of their trip from the analysis.

Public bikeshare programs offer an alternative and accessible mode of transportation that is active and environmentally conscious. However, they should not only be seen as a substitution to public transit. A majority of weekday trips are already integrating bikeshare and public transit, which justifies further investment into bikeshare programs. Continued popularity of bikeshare will reduce dependency on cars and congestion in urban areas. The findings of this study can also be used to determine when and for what purpose riders are using bikeshare, informing effective policies to incentivize ridership and increase access in underserved communities. We ought to consider bike sharing not only as an alternative to public transit, but also as a way to increase overall ridership for both modes of transportation.

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Kong, Hui, Scarlett T. Jin, and Daniel Z. Sui. 2020. “Deciphering the Relationship between Bikesharing and Public Transit: Modal Substitution, Integration, and Complementation.” Transportation Research Part D 85, August 2020. https://doi.org:10.1016/j.trd.2020.102392.

Bullock, C., Brereton, F., Bailey, S., 2017. “The economic contribution of public bike-share to the sustainability and efficient functioning of cities.” Sustainable Cities and Society 28, 76–87. https://doi.org/10.1016/j.scs.2016.08.024.

Fishman, E., Washington, S., Haworth, N., 2014a “Bike share’s impact on car use: Evidence from the United States, Great Britain, and Australia.” Transportation Research Part D: Transport and Environment 31, 13–20. https://doi.org/10.1016/j.trd.2014.05.013.