Vehicle Routing Problem of Simultaneous Deliveries and Pickups with Two-Dimensional Loading Constraints

With the development of reverse logistics, the vehicle routing problem with simultaneous deliveries and pickups has received increasing attention. The existing research mainly considers the weight restriction, but in daily distribution, there are a number of light cargoes whose bulk usually restrict the vehicle load. To solve the problem, this paper studies the vehicle routing problem of simultaneous deliveries and pickups of two-dimensional loading constraints (2L-CVRPSDP), in which each customer has a two-dimensional rectangular item with different sizes and weights, and the objective is to find a set of routes with the minimum cost under the loading and capacity constraints. An improved iterated local search algorithm is proposed to solve it. The method uses the improved saving algorithm to produce the initial solution, subsequently adopts 2-opt exchange, 2-opt* exchange, 1-0 exchange, 1-1 exchange, cross-exchange, and or-opt exchange. Finally, the computational results show that the algorithm can effectively solve the problem. The study is helpful to provide decision support for logistics enterprises.