Bus Routing Problems: Coupling of Optimization Methods and Simulation

In a demanding economical context, public transport companies search for decision making tools to guide them in the improvement of their transport offers in urban networks. From this perspective, we present two models. However, in view of an optimization problem, two major possibilities conflict: define a mathematical model and solve it with advanced optimization techniques, or define a simulation model and explore some possibilities in order to find a good solution. Both approaches have their drawbacks: the first one usually finds an optimal solution, but is based on a too simplified model; the second one uses a more complete model, but the exploration of the possibilities is limited. We present here a new coupling attempt of the optimization methods with the simulation, in order to take advantage of both approaches. After a presentation of the models, we explain the resolution methods we choose. We propose then to use the simulation to refine the data of these models in order to obtain good practical solutions.