Multiple Periods Vehicle Routing Problems: A Case Study

In this paper, we consider a challenging problem faced by a hygiene services company. The problem consists of planning and routing a set of customers over a 3-month horizon period where multiple frequencies of visits can be required simultaneously by each single customer. The objective is then threefold: (1) balancing workload between vehicles (agents) (2) minimizing number of visits to the same customer (3) minimizing total routing costs. In this context, a routing plan must be prepared for the whole horizon, taking into account all constraints of the problem. We model the problem using a decomposition approach of planning horizon, namely, weeks planning and days planning optimization. We propose an adaptive large neighborhood search with several operators for routing phase of solving approach. To evaluate the performance of the solving approach we solve an industrial instance with more than 6000 customers and 69951 requests of visits. The results show an excellent performance of the solving approach in terms of solution quality compared with the existing plan used by the hygiene services company.