Designing salespeople's routes with multiple visits of customers: A case study

In this paper, we present a procedure for designing the routes for the salespeople that work for the commercial network of a home video company. The commercial area is divided into different zones and each salesperson is assigned to one of them, working and having independent routes from the others. The company wanted to generate salespeople's routes for a commercial cycle, which is usually one month long. The commercial cycle has the following main features: each customer has to be visited a specific number of times (from 1 to 5); and two-day routes are possible when the customers are located far from the salesperson's residence. After the set of routes is generated, each salesperson assigns his/her own routes to each working day, taking into account local holidays, national meetings and other unforeseen events. The objective function is to minimize the weighted sum of the travel time plus overtime penalties. In less than one month, an ad hoc procedure was designed, coded and calibrated. The company has qualified the routes as very satisfactory and the tool is now used by the commercial network management to: reassign customers, assign new customers and vary the number of visits to the customers.