Combining bus evacuation with location decisions: a branch-and-price approach

In this work, we consider a bus evacuation problem with integrated location decisions as part of a decision support system. Apart from giving a bus schedule, our model helps planners to choose the locations where people gather and the shelters that are used during the evacuation. Following a branch-and-price approach, the location and scheduling problems are solved simultaneously to achieve a minimal evacuation time. Using an instance modelling the evacuation of Kaiserslautern, Germany, we demonstrate that although the computational complexity of the model increases compared to solving the subproblems individually, the model is still tractable. Furthermore, our algorithm also finds a good feasible solution much faster than commercial general integer programming solvers and can, thus, also be used as a heuristic. (C) 2014 The Authors Published by Elsevier B.V.