Optimal location of free-floating bike-sharing dispatching hubs: A multi-scale perspective

Free-floating bike-sharing (FFBS for short) dispatching, the process by which operators redistribute shared bikes, is essential to satisfy FFBS demand and alleviate the “tidal phenomenon” of the FFBS system. However, the efficient formulation of dispatching strategies for FFBS systems is usually constrained by factors such as the spatial extent of the dispatching region and the length of the scheduling path. In this study, we propose an FFBS dispatching hub siting framework from a multi-scale geographic view, to provide more refined spatial units for developing FFBS dispatching strategies. More concretely, firstly, on a macro-scale, the entire study area is divided into multiple cycling communities (i.e., FFBS management sub-regions) with closer internal connections. Secondly, a hybrid spatial clustering method is developed to identify FFBS virtual stations with a certain service radius at the micro-scale. Finally, exploiting the location-allocation model, we optimize the siting of FFBS dispatching hubs within each management sub-region to maximize the coverage of virtual stations and FFBS demand within their catchment area (meso-scale). The feasibility of the proposed framework is empirically investigated using the FFBS system in Nanjing, China as a case study. The resulted dispatching hubs for each management sub-region unveil that 50 dispatching hubs selected from 147 urban rail transit stations can cumulatively cover 70.10 % of the number of virtual stations and 87.52 % of the FFBS demand within their catchment area (3000 m). Our findings could help stakeholders improve the efficiency of dispatching schemes, thereby providing more rational and targeted decisions for reducing the dispatching path length and increasing the bike turnover rate.