A two-echelon multi-trip vehicle routing problem with synchronization for an integrated water- and land-based transportation system
研究了水陆一体化运输系统中的两层级同步物流问题，提出混合整数线性联合模型和逻辑Benders分解模型，优化转运和卫星分配，降低整体物流成本，实验表明新模型在大规模实例中可平均降低10.6%的总成本，并减少20%-30%的街道车辆行驶里程。
This study focuses on two-echelon synchronized logistics problems in the context of integrated water- and land-based transportation (IWLT) systems. The aim is to meet the increasing demand in city logistics as a result of the growth in transport activities, including parcel delivery, food delivery, and waste collection. We propose two models, a novel mixed integer linear joint model, and a logic-based Benders’ decomposition (LBBD) model, for a two-echelon problem under realistic settings such as multi-trips, time windows, and synchronization at the satellites with no storage and limited resource capacities. The objective is to optimize transfers and satellite assignments, thereby reducing overall logistics costs for street vehicles and vessels. Computational experiments demonstrate that the LBBD model is more robust in terms of solution quality and solution time on average while the added value of the LBBD is more evident when solving large-scale instances with 100 customers, reducing the overall costs by 10.6% on average and significantly reducing the fleet costs on both networks. Furthermore, we assess the effect of changing cost parameters and satellite locations in the proposed IWLT system–analyzing system behavior and suggesting potential improvements–and evaluate several system alternatives in city logistics–consisting of different transportation network designs (single- and two-echelon), vehicle types, and operational constraints. On average, the proposed two-echelon IWLT system reduces the number of kilometers traveled by vehicles at street level by ranging from 20% to 30% compared to a typical single-echelon service design that relies solely on trucks. • A compact formulation for a rich variant of synchronized two-echelon routing problem. • A logic-based Benders decomposition (LBBD) to tackle the complexity of the problem. • Managerial insights on the benefits and challenges of synchronized IWLT systems.