Study On The Route Optimization Of Urban Hazmat Transportation Problem Under Time Limit

With the rising accident rate of hazardous materials vehicles in our country,route optimization of distribution vehicles is an important aspect of hazardous materials transportation safety.From the point of view of considering the time factor in the transportation of hazardous materials vehicles,the government stipulates that the transportation of hazardous materials vehicles in all provinces has a strict traffic restriction system,as well as the changes in traffic flow,the number of people near road sections and the satisfaction of customers with the delivery time.This series of practical reasons reflect the importance of the time factor to the route optimization of hazardous materials vehicles.From the point of view of carrying capacity of hazardous materials vehicles,it is mainly reflected in the fact that the more real-time carrying capacity of hazardous materials vehicles is.If accidents occur during the transportation of hazardous materials,the more exposed the population is,the more difficult the rescue is,the more serious the losses are,and the consequences are unimaginable.Therefore,this paper considers the establishment of a hazardous materials transportation vehicle route optimization model that minimizes the number of vehicles,transportation distance and transportation risks under the conditions of the government’s restriction policy and the time limit of the distribution time window,and compares and analyzes the obtained risk analysis results with the original hazardous materials transportation vehicle route selection scheme.Firstly,this paper proposes a multi-objective evolutionary algorithm based on probability model.The algorithm uses non-dominated sorting method to select population,and further uses the idea of statistical learning to establish a multi-objective optimization model.In order to verify the effectiveness of the proposed model and algorithm,three different sets of calculation examples are designed according to the different geographical distribution of transportation network nodes.Secondly,by improving NSGA2 algorithm,the results of the three groups of cases are compared and analyzed,and then the Pareto solution set obtained by the example of clustering distribution is specifically analyzed.Finally,taking a regional road network in Xi ’an City of Shaanxi Province as an example,the risk evaluation model of hazardous materials transportation vehicles is established,and the improving NSGA2 algorithm is used to solve the model by Matlab software.Considering the universality of the example data,the hazardous materials transportation routes in tier 1 and tier 2 cities are also studied,and the best route of hazardous materials transportation is obtained.According to the analysis of hazardous materials transportation in Xi ’an,the best transportation route obtained by the optimization model of dangerous goods transportation vehicle route selection constructed in this paper is better than the actual transportation route.At the same time,the real-time change of time factor and cargo capacity will have certain influence on the choice of transportation scheme for hazardous materials.