A new mathematical model of vehicle routing problem based on milk-run

Aiming at the main problems of low loading rate of vehicles, poor arrangement efficiency of routes, high costs for distribution and collecting the parts without the time window provided by a certain vendor in the milk-run process of enterprise operation, a new mathematical model called Time Window Priority Model (TWPM) is established based on the concept of the milk run system in order to solve vehicle routing problem. The objective function of the model is to minimize the sum of the milk-run mileage and waiting time that can be expressed by distance and the constraints of the model are hard time window provided by a certain vendor and the rated volume of the van trucks. Then, we design an algorithm for the TWPM. An-example based on the actual data of an auto enterprise is used to test the feasibility of the model and the algorithm of the TWPM in solving vehicle path problem.