A two-stage robustness approach to evacuation planning with buses

• A two-stage bicriteria model for bus evacuation with data uncertainty is proposed.
• An iterative solution algorithm is developed.
• Realistic datasets for Kaiserslautern, Germany, are used.
• The algorithm is suitable for practice due to sufficiently small computation times.

We consider the problem of scheduling a bus fleet to evacuate persons from an endangered region. As most of the planning data is subject to uncertainty, we develop a two-stage bicriteria robust formulation, which considers both the evacuation time, and the vulnerability of the schedule to changing evacuation circumstances.As the resulting integer program is too large to be solved directly using an off-the-shelf solver, we develop a scenario-generation algorithm which iteratively adds new scenarios to the incumbent subproblem being solved. Computational experiments show that this approach is fast enough to solve a realistic instance corresponding to an evacuation case within the city of Kaiserslautern (Germany).