The close-open mixed-fleet electric vehicle routing problem

The market of Electric Vehicles (EVs) has grown significantly in recent times. The transportation sector is expected to shift to EVs as well, but there are several significant challenges that make the shift difficult, mainly their capacity for transporting heavy payloads and their high acquisition costs. This research explores a novel business concept wherein a logistics company owns a small fleet of EVs, and rents additional EVs as needed, while providing the option to charge the owned EVs only after completing the final delivery. This concept is modeled as a Close-Open Mixed-fleet Electric Vehicle Routing Problem (COMF-EVRP), and the mathematical formulation is presented. Instances from the literature are adapted for the COMF-EVRP. To solve large instances, three discrete optimization swarm intelligence algorithms are employed, alongside a Variable Neighborhood Search algorithm. Lastly, a comprehensive evaluation of these algorithms' performance on the COMF-EVRP is provided.