Investigation of modal integration of bike-sharing and public transit in Seoul for the holders of 365-day passes

Bike-sharing has a mixed relationship with public transit-characterized by modal integration and modal substitution-and affects the public transit ridership. In previous studies, to investigate the relationships between public transit and bike-sharing, analyses based on either surveys or analysis based on trip record data have been conducted; thus, there have been several limitations to obtaining accurate and large data to reveal the relationships between public transit and bike-sharing. Unlike previous studies, owing to the mileage program of Seoul Bike, this study investigates the modal integration of bike-sharing and public transit using only trip records of bike-sharing integrated with public transit for the holders of 365-day Seoul Bike passes in detail using explanatory data and regression analyses. Additionally, considering that the relationship between bike-sharing and public transit might vary according to the mode of public transportation, this study investigates the spatio-temporal patterns of modal integration between bike-sharing and public transit, and the factors that influence the modal integration at the station level using binomial regression. The results indicate that the effects of various factors on the modal integration depend on the distance to the nearest subway station and the time when the trip occurs (weekdays or weekends and certain periods during the day). This study also suggests that the relationship between bike-sharing and public transit may vary according to the public transit mode. Although shared bikes seemed to be used in conjunction with both the subway and bus, the proportion of modal integration between bike-sharing and public transit among all trips using 365-day passes is likely to be affected more by the subway system than the bus system, especially for regular commutes. Furthermore, it is observed that shared bikes can be used to avoid overcrowded buses in connection with subways.