A two-stage robust satisficing model for equitable EV-sharing system with parking-charging slots

Electric vehicle (EV) sharing systems play a key role in sustainable urban mobility. This study focuses on optimising the deployment of EVs, parking slots, and charging infrastructure in one-way station-based EV-sharing systems. We propose a two-stage robust satisficing model that integrates both equity and profit considerations. In the first stage, strategic decisions on EV-sharing system design, including EV deployment and parking and charging facility installation, are determined. The second stage balances service equity and operational profit, where equity is quantified based on regional disparities in service fulfillment and profit is measured through earned revenues. The two-stage model is reformulated as a semi-infinite mixed integer linear program (MILP) and a constraint generation algorithm is designed to solve it exactly. Numerical experiments based on a real-world case in Chicago demonstrate the effectiveness of our proposed approach. The results reveal that incorporating equity considerations leads to a more balanced spatial distribution of facilities, avoiding excessive concentration in high-demand areas. Additionally, we find that when system demand is low, considering both equity and profit can enhance overall revenue compared with a profit-only strategy. As for the high-demand profile, equity considerations have a negligible impact on compromising profit. These insights highlight the importance of integrating equity into EV-sharing system planning to achieve both social and economic benefits.