As already mentioned, the demand data are estimates based on average daily observations carried out during the
first two working weeks of the year 2006 (just after the Christmas holidays). To verify the stability and robustness of
the solutions, we generated 1000 perturbations in the original demand matrix. For each perturbed matrix, we measured
the value of the objective function for each of the solutions (i.e., route designs and bus assignments) obtained in the
experiment on real data