Multi-type Products Collaborative Vehicle Routing Problem Under Consideration Of Transshipment

With the rapid development of the economy,the development of China's logistics industry is becoming more and more rapid.Road transportation industry,as one of the world's major modes of transport of goods,has also developed rapidly.The increasing number of logistics enterprises also means that the competition between logistics enterprises is becoming more and more intense.Road transportation carriers are facing increasing competitive pressures due to the rising price of oil and the improving of demand of customer service.Carriers have to find ways to reduce the transportation cost and then improve their profit due to the increasing competition pressure.For small and medium sized carriers,it is difficult to further reduce cost through their own abilities and resources,and cooperation with the peer carriers called horizontal cooperation is an effective way to reduce their transportation costs.Through horizontal cooperation,carriers can share orders and facilities to improve resource utilization and plan more efficient transportation routes to reduce their transportation costs.The related vehicle routing problem of horizontal cooperation is called collaborative vehicle routing problem(CoVRP).The CoVRP can be divided into two kinds of problems which is called single-type products CoVRP and multi-type products CoVRP according to whether the goods delivered by carriers of the horizontal coalition are homogeneous or not.The paper is based on multi-type products CoVRP.The conventional multi-type products CoVRP has some limitations.In order to address the problem,we introduce multi-type products CoVRP with transshipment.The specific research contents are as follows:(1)For the the multi-type products CoVRP with transshipment,A mixed-integer linear programming model for this problem is established.Instances are solved by using ILOG CPLEX for non-cooperation scenario,conventional cooperation scenario,cooperation with transshipment scenario.Computational results show that the cooperation of the carriers can achieves significant cost-saving compared to the non-cooperation scenario.Further cost-saving can be realized by introducing transshipment into the cooperation and when the distance between the depots of carriers is relatively far.However,some experimental data show that in some extreme cases the addition of transshipment can sometimes reduce cost savings.(2)In order to avoid the extreme situation,I improved the previous model.Instances are solved by using ILOG CPLEX for non-cooperation scenario,conventional cooperation scenario,cooperation with transshipment scenario,improved cooperation with transshipment scenario.Computational results show that the improved collaborative transportation with transshipment is obviously better than the conventional collaborative transportation and further cost-saving can be realized by introducing transshipment into the cooperation.