Routing and scheduling decisions for a single-hub same-day delivery network

The present research addresses the problem of routing and scheduling in a home delivery network with distinct pickups and deliveries. A fleet of capacitated vehicles belonging to the only hub center of the network transports the demands between the network nodes. The proposed mixed integer programming model minimizes the total transportation costs in a situation where demand splitting is possible. This model can be used in general hub networks and many-to-many networks. Due to the complexity of the problem, valid inequalities are used to reinforce the formulations. Then, a genetic algorithm serves to solve problems of various sizes. The performance of the reinforced model along with the valid inequalities and the genetic algorithm is examined through a case study of a same-day postal delivery company. The computational results show the good performance of the solution methods.