Abstract: In order to improve the three-level logistics distribution system in counties and villages and complement the shortcomings of rural delivery logistics infrastructure, the mode integrating passenger, cargo and express mail service emerges. The integration of passenger, cargo and express mail service is mainly implemented through passenger vehicles. However, due to the low frequency of passenger vehicles in rural areas, the mentioned integration faces problems such as high operating cost of passenger vehicles and long delivery time during implementation. To address the issues of operating cost and the delivery of passengers and cargo, a bi-level programming model for coordinated vehicle scheduling is established by considering the scheduling optimization of urban and rural passenger vehicles integrating of passenger, cargo and express mail service. It can optimize the fleet size and improve the efficiency of express delivery in rural areas. The upper-level programming model takes the minimum of total travel time of passengers and cargo as the objective, while the lower-level programming model takes the minimum of fleet size as the objective. The deficit function is used to transform the lower-level objective into the constrain of the model, and the optimal solution of the bi-level programming model is obtained based on a deterministic fleet size. Through numerical example analysis, the differences in total travel time between the integration of passenger, cargo and express mail service and the separation of passengers and goods are compared. Results show that considering the integration of passenger, cargo and express mail service can effectively reduce the total travel time of passengers and cargo with different fleet sizes.

Key words: integration of passenger, cargo and express mail service, bi-level optimization, vehicle scheduling, deficit function