Distribution Routing Optimization Of Cold Chain Logistics With Consideration Of Road Traffic Conditions

Cold chain logistics distribution has strong perishable characteristics and timeliness, goods quality declines along with the growth of the delivery time. Cold chain distribution activity mainly occurs in city, then increasingly serious urban road congestion delays vehicles traveling time, reduces the quality of goods and service efficiency, increases the costs of cargo damage and energy consumption, affects the quality of cold chain logistics distribution. The relevant statistics show that our country loses hundreds of billions of dollars in food circulation every year. This highlights the necessity and realistic significance of considering traffic condition in the process of cold chain logistics distribution optimization.At present, in view of the route optimization problem of cold chain logistics distribution, the domestic and foreign literature are studied to some extent, which generally can be categorized into three aspects:(1) in view of the cold chain distribution, the temperature monitoring and the changing rule of cargo quality; (2) the improvement research of route optimization model of cold chain logistics distribution; (3) improving the algorithm of route optimization of cold chain logistics distribution problem. Some of literatures consider the time variation of vehicle speed in the optimization model, and take a step function as the velocity expression. But it has defect that traffic status is uncertain, vehicle speed is influenced by the traffic state, then the traffic state of different route or different driving time may be different, so only using the step function can’t accurately reflect the influence of vehicle speed being affected by the traffic status.On the basis of the above researches, this paper searches the distribution route optimization problem of cold chain logistics which considers the road traffic conditions. Considering the uncertainty of traffic situation, this paper divides time into several intervals and gives five traffic cases. Based on the theory of the road unblocked probability and the fuzzy synthesis judgment method, the unblocked probability of each road in each period can be converted into road traffic conditions; Based on the theory of road impedance function proposed by the highway bureau, the distribution distance can be converted to vehicle traveling time of different traffic condition. On the basis of the road traffic conditions and vehicle traveling time, structuring the cost function of transportation、cargo damage、energy consumption and penalty, establishing the optimization model of distribution route which considers the road traffic condition. Using the 2-opt local search algorithm improves the mutation operation, so as to enhance the local search ability of genetic algorithm. Using matlab computer simulation to solve the optimization model that verifies the rationality and validity of the model built in the paper and the optimization algorithm. Comparison and analysis of the optimization results, it shows that considering the road traffic condition in the cold chain logistics distribution route optimization has important practical significance, especially the cold chain logistics distribution route selection with the worse road traffic condition.