Reducing the Risk of Robbery in Flexible Periodic Vehicle Routing Problem

This study proposes the flexible periodic routing problem for vehicles, which are carrying cash and valuable goods. Each customer has a visit frequency, and the demand to be met at any visit is predefined. The visit schedules are not fixed, and a fleet of homogenous vehicles carries the cash and valuable goods from the depot to customers. This problem restricts the risk of vehicle robbery by avoiding carrying cash in similar routes in consecutive periods. A set of instances are updated from literature for the proposed problem. A mixed integer linear programming formulation is developed, and small instances are solved using IBM CPLEX. Since the problem is NP-hard, we present a population-based simulated annealing algorithm to deal with large size instances. The experimental results show the good performance of our proposed algorithm for safe transportation of cash and valuable goods on a periodic horizon.