Effective heuristics to solve pickup and delivery problems with time windows

Pickup and delivery problem with time windows (PDP-TW) is a challenging scheduling problem for which each delivery is coupled with a pickup request. Metaheuristic search techniques like the tabu search have been used to solve PDP-TW. In this paper, we investigated a min-conflicts based micro-genetic algorithm combining some interesting construction heuristic, namely the Align-Fold or Boomerang, and repair heuristics including a new swap operator and a modified billiard operator to effectively solve PDD-TW. Our results compared favorably against those of a tabu-embedded metaheuristic search on a set of modified Solomon´s test cases. More importantly, our proposed heuristics can easily be integrated into many search schemes for solving other complex scheduling problems.