Abstract
This study investigates vehicle operating time as a constraint within the vehicle routing problem (VRP) with multiple trips (VRPMT). In the basic VRP, a single route is assigned to each vehicle and the solution must satisfy both the load and distance (or travel time) constraints. However, in the real-world problem, one vehicle is assigned to multiple routes per day. Since this becomes a large-scale combinatorial optimization problem, it becomes difficult to ?nd an exact solution. Therefore, in previous research, a heuristic method using a two-phase algorithm was proposed. However, since the precision of the two-phase algorithm is greatly in?uenced by the solution selected for the ?rst phase, selection of solutions in this phase is crucial. In this study, the advantages of the one- and two-phase methods are integrated in a new proposed method.
