Free-floating bike-sharing green relocation problem considering greenhouse gas emissions

This paper introduces the problem of green bike relocation considering greenhouse gas emissions in free-floating bike-sharing systems (FFBSSs) and establishes a mathematical model of the problem. This model minimizes the total imbalance degree of bikes in the FFBSS and the greenhouse gas emissions generated by relocation in the FFBSS. Before the relocation phase, the FFBSS is divided into multiple relocation areas using a two-layer clustering method to reduce the scale of the relocation problem. In the relocation phase, the relocation route problem is converted into a pickup and delivery vehicle-routing problem. Then, an adaptive variable neighbourhood tabu search algorithm with a three-dimensional tabu list is proposed, which can simultaneously solve the relocation problem and the routing problem. A computational study based on the actual FFBSS used in Shanghai shows that this method can effectively solve the green relocation problem of FFBSSs.