Rebalancing an E-Scooter-Sharing System with En-Route Charging Capability

Abstract

The proliferation of e-scooter fleets complements urban transportation by providing flexibility and convenience. However, these fleets also face operational challenges, particularly in e-scooter rebalancing and battery recharging, which are crucial for maintaining desired service levels. This paper explores an innovative operational concept of en-route charging, where e-scooters are recharged while being transported between locations on rebalancing vehicles. When managed effectively,  operations of rebalancing and recharging offer substantial benefits to e-scooter fleet operators and urban transportation users. We present a novel integrated decision model (IDM) that jointly addresses routing, waiting, and handling decisions to meet service-level requirements and maximize profit. To tackle computational challenges, we decompose decisions into two stages and prove the total unimodularity (TU) of the second-stage problem's coefficient matrix. This property allows us to simplify the second-stage integer program to a manageable linear program without sacrificing solution quality. An extensive numerical study based on a real-world shared e-scooter system in Minneapolis, leveraging the TU property, demonstrates computational efficiency improvements of 2.68 times and 4.95 times with 20 and 30 gathering points, respectively. Additionally, significant advantages are observed with even larger numbers of gathering points. The study also quantifies the economic benefits of en-route charging, revealing an average total profit increase of $241.60 (9.0%) compared to a centralized recharging approach. Furthermore, we address the equity aspect of operations, showing that enforcing fairness requirements results in a negligible average profit loss of $2.03 (0.07%) of the daily operations. These findings provide valuable insights for both system operators and policymakers, highlighting the operational and economic advantages of en-route charging in e-scooter fleet management.

Keywords: E-scooter rebalancing · en-route charging · centralized recharging · fairness operations