Depot location in degradable transport networks

• A new approach to depot location in degradable transport networks for humanitarian logistics is presented.
• Hyperpaths are generated that offer an adequate number of alternative routes.
• Hyperpath costs are used for depot location.
• A heuristic is required to solve the depot location problem for many candidate sites.
• Two drop heuristics are presented, one for assigning integer numbers of population centres to depots, the other relaxes the integer constraint.
• The combined hyperpath and depot location method is tested on a small numerical example based on the 2008 Sichuan earthquake.

Areas subject to natural or man-made disasters, such as earthquakes, fires, floods or attacks, are reliant on the residual transport network for the rescue of survivors and subsequent recovery. Pre-disaster planning requires assumptions about how the transport network may degrade. This paper presents a game theoretic approach modelling network degradation and applies this to depot location, with a case study based on Sichuan province in China, which is prone to earthquakes. To facilitate a cautious approach to depot location, the method assumes that the transport network is subject to attack by node-specific demons with the power to degrade links. The mixed strategy Nash equilibrium for the non-cooperative zero sum game between dispatchers and demons is used to define rescue hyperpaths. These in turn define the best depot locations. Two forms of the drop heuristic are used to find good depot locations.