Abstract
Vehicle routing problem with soft time windows and simultaneous pickups and deliveries (VRPSTWSPD), which illustrates a class of distribution and routing systems of convenience store industry, is introduced. The VRPSTWSPD is a novel variant, where it combines characteristics of two existing variants in the literature. A mathematical model of the VRPSTWSPD is first developed in the paper. A branch-and-price exact-based procedure with a two-stage subproblem solution algorithm for solving small-sized instances is then described, followed by an efficient genetic algorithm metaheuristic-based procedure taking into account intermediate infeasible search strategy, which is more adequate for larger instances. Both solution algorithms were successfully tested on benchmark instances. The exact solutions can be used as references to evaluate the performances of the proposed genetic algorithm.
