Static repositioning in bike sharing systems with broken bikes

Abstract

The Bike Sharing System (BSS) has been receiving increasing popularity in transportation plans. To distribute bikes reasonably across stations to cater for the time-related demand, bikes need to be moved among stations using a fleet of vehicles. This process is the bikes repositioning. Besides the transshipment of good bikes, all broken bikes need to be carried back to the depot to repair. This research aims to handle both good and broken bikes in a bike sharing network in order to achieve the perfect balance between demand and supply and make sure all broken bikes are moved back to the depot. The objective of this repositioning operation is to minimize the total CO₂ emission of the repositioning vehicle during the whole journey. In this research, a Mixed Integer Linear Program (MILP) model is presented to describe the problem mentioned above and a commercial solver is used to solve it. Problem characteristics are dissected by analyzing factors that would affect emissions. The results indicate that the proposed model can describe the problem properly and the emission will be affected according to different constraint settings.