Operations for free-floating bike sharing systems: a literature review

In the last decade, bike sharing systems have emerged in cities to propose a sustainable and convenient way to realize last mile trips. They can be with (station-based bike sharing systems, SBBSSs) or without stations (free-floating bike sharing systems, FFBSSs). With a FFBSS, users can find the closest bike available in the city thanks to an app on their phone, rent it, realize their trip, and lock the bike anywhere in the city. The FFBSS offers more flexibility to users than the SBBSS but brings some specific challenges, such as the disorderly parking, the congestion of sidewalks, the large number of bike locations, and the complex redistribution operations. The scientific literature has addressed those challenges and the FFBSS operations. We review it by tackling three main subjects. The first one focuses on discretizing the bike locations by dividing the geographical area where a FFBSS is active into zones. This operation is necessary because the number of bike locations is higher with a FFBSS than a SBBSS. The second subject consists in forecasting the rental demand in each zone, helping to satisfy user demand and to improve the utilization rate of the system. The last topic focuses on redistribution models, to maintain a desired quantity of bikes at each zone by moving bikes from one place to another. We conclude by highlighting the research directions in the field of FFBSS operations identified in the literature