ELECTRIC VEHICLE ROUTING PROBLEM WITH BACKHAULS INTEGRATED WITH DETERMINING THE LOCATION OF CHARGING STATIONS: A REAL-LIFE PROBLEM

Companies are increasingly tending to replace their conventional fleets with electric vehicles (EVs), primarily driven by carbon policies. However, EVs face challenges such as limited driving range and the necessity for dedicated charging infrastructure. Given that the requirements of linehaul and backhaul customers are relatively consistent over time, the long-term operational costs of weekly routing often outweigh the one-off investment of installing charging stations. Furthermore, since EV charging is time-consuming, performing this process during loading or unloading operations offers a significant advantage by minimizing route completion time. To address this, this study proposes a two-stage mathematical modeling approach designed to prioritize operational efficiency. In the first stage, routes are constructed solely to minimize total travel costs, ensuring the most lean logistics operation. The second stage then determines the optimal locations for charging stations by minimizing their total number based on the pre-established routes. This hierarchy allows decision-makers to focus on routing stability before committing to infrastructure. To validate this framework, an integrated approach encompassing both routing and station determination was also developed. Both methodologies were applied to a case study in Turkey. The results provide evidence suggesting that the two-stage approach yields more encouraging outcomes, offering a practical and effective strategy for transitioning to electric fleets.