A routing and scheduling method in considering trade-off between the user’s and the operator’s objectives

A routing and scheduling model is proposed for the one depot, multi-vehicle, many-to-one, and vehicle capacity constraint problem. The model takes both the operator’s and the user’s objectives into account. The operator’s objective is assumed to be the minimization of transportation cost or distance travelled; while the user’s objective is represented by the minimum time difference between the desired and the actual times of vehicle arrival. The routing model is based on the classical Clarke-Wright algorithm; however, node pairs in the model are ranked by an index generated by the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Thus, unlike the traditional Clarke-Wright model, this model incorporates not only transportation cost but also the desired time of vehicle visit in the route development. Furthermore, different sets of routes can be produced depending upon the degree of preference attached to each objective. A step-by-step computation procedure and a set of examples are also presented.