A bi-objective model to increase security and reduce travel costs in the cash-in-transit sector

In this paper, we present a variant of the vehicle routing problem (VRP) to increase security in the cash-in-transit sector. A speci?c index is used to quantify the exposure of a vehicle to the risk of being robbed along its route. In addition, the problem is subjected to a traditional capacity constraint, according to which a maximum amount of valuables can be transported inside the vehicle. Th?is constraint might be imposed, for example, by insurance companies. A bi-objective formulation, aimed at reducing both the risk and the travel cost, is proposed. Th?e objectives are con?flicting since higher risk exposures allow a reduction of the travel cost needed to visit and collect valuables from all customers. A mathematical model of the problem is proposed and solved by using a progressive multi-objective metaheuristic. Realistic instances are also generated considering the geographical coordinates of several customers (e.g., stores, banks, shopping centres) located in Belgium. Th?e proposed solution approach is tuned and tested both on these realistic instances and on standard benchmark instances for the capacitated vehicle routing problem.