A multicriteria dial-a-ride problem with an ecological measure and heterogeneous vehicles
Résumé
The Dial-a-Ride Problem is a complex combinatorial optimization problem with many real-world applications in transportation of persons. It consists in routing a fleet of vehicles based at a common depot in order to satisfy users' transportation requests. Each request may consist, in a number of persons, a specified pickup location, a destination location, desired departure and arrival time windows. In this paper, we investigate a new and general model for the transportation of persons. It involves three objective functions that have to be optimized in order to measure the potential efficiency of the Dial-a-Ride Problem solution on different aspects: the cost for the transportation operator, the quality of service for users and the impact on the environment. For an efficient search through the solution space, we use a multiobjective genetic algorithm, which allows us to identify a good approximation of the set of Pareto optimal solutions. Among this set of solutions, the decision-maker can select the solution with best compromise according to its preferences, without introducing a priori information about these ones. The proposed genetic algorithm is based on an optimal timing algorithm that computes pickup and delivery dates when the requests are sequenced on the vehicles