A Set Covering Approach for the Pickup and Delivery Problem with General Constraints on Each Route

Abstract

We consider a generalization of the pickup and delivery problem with time windows by allowing general constraints on each route, and propose a heuristic algorithm based on the set covering approach, in which all requests are required to be covered by a set of feasible routes. Our algorithm first generates a set of feasible routes, and repeats reconstructing of the set by using information from a Lagrangian relaxation of the set covering problem corresponding to the set. The algorithm then solves the resulting set covering problem instance to find a good feasible solution for the original problem. We conduct computational experiments for instances with various constraints and confirm the flexibility and robustness of our algorithm.