Vehicle crew scheduling to complete specific tasks and bulk-tasks at depots

In the vehicle crew scheduling problem, which is the topic of this paper, the authors consider several depots, and each operator is based at one of these depots. The workday of each operator is specified in terms of specific tasks and a share of the bulk-task of this depot. The model is formulated as a set-covering problem with additional constraints. The solution approach includes three major steps. First, several reasonable schedules are generated with regard to union contract regulations. Then the corresponding set-covering problem with additional constraints is solved with a branch-and-bound procedure. Finally, this solution is modified and improved by reorganizing the sharing of the bulk-tasks among operators. Numerical results are reported for problems in context of postal vehicle crew scheduling.