Research On Emergency Logistics Transportation Organization Method Considering Time And Space Changes In Road Network Environment

China is one of the countries most seriously affected by emergencies in the world.The occurrence of emergencies has brought serious impact on people’s normal life,and caused heavy casualties and economic losses.Under emergencies,the emergency logistics road network is an important carrying facility for the distribution of emergency materials.According to the characteristics and possible hazards of emergencies,it is an important measure to improve emergency management capabilities to establish a scientific emergency logistics and transportation organization method.In real life,in order to minimize the harm caused by emergencies,when a disaster occurs,it is a crucial part of the entire emergency process to efficiently distribute emergency materials to each emergency material demand point within a specified time.Emergency logistics and transportation organization is a complex system engineering.To ensure the high efficiency of emergency material distribution,the scientific problem is to build a set of emergency logistics and transportation organization that considers the temporal and spatial changes of the road network environment when the city encounters major emergencies.It also considers the distribution factors that are closer to the actual situation in the emergency material distribution process under the real road network,such as distribution vehicles,time urgency,traffic flow,road environment,etc.In order to realize the emergency logistics transportation organization method that considers the temporal and spatial changes of the road network environment,this paper starts from the emergency logistics network and scheduling planning theory,and considers the basic related issues of emergency logistics transportation organization in the complex temporal and spatial environment.Starting from the perspective of "point",that is,the distribution node,gradually considering the influence of "line",that is,related research on distribution roads,and finally considering the "surface" comprehensively,that is,considering the overall change of the road network environment,with the actual road network as the background,constructed the following three research models:1)Time window model for optimal scheduling on vehicle distribution of emergency materials.After the occurrence of an emergency,the demand for emergency materials has surged in a short period of time,and the urgency of emergency material demand at each emergency material demand point is different,resulting in different time windows for the arrival of emergency materials at the emergency material demand point.The minimum number of delivery vehicles And the distribution channel as the goal,build the emergency distribution vehicle scheduling time window model.Through this model,a vehicle distribution and transportation coordination scheme considering multiple time window constraints is realized.Under the background of emergencies,for any road network,the corresponding relationship between each emergency material demand point and each emergency material distribution center can be formulated,with the least number of vehicles.At the same time,we set out to meet the time requirements for the delivery of emergency materials at each emergency material demand point,and ensure a more comprehensive,reasonable and efficient overall road network emergency logistics and transportation organization..2)Traffic flow restricting model of branch road in distribution routes of emergency materials.Due to the real-time changes in road traffic flow,there is a situation where intersections merge,resulting in road congestion and reduced traffic capacity.Comprehensively considering the real-time traffic conditions of the road after an emergency occurs,by changing the traffic restriction at intersections and the distribution path of emergency materials,with the goal of minimizing the delivery time and cost,the genetic algorithm is used for coding design,and the emergency material distribution path is constructed.Branch current limiting model.Through this model,in the process of emergency material distribution under emergencies,the start and end time of flow restriction of each branch road intersection connected to it in any distribution road can be determined,so that the distribution vehicles can greatly reduce the distribution on this road.Time,and the impact on the number of urban traffic vehicles is minimized,making the entire emergency logistics system more efficient.3)Consider an emergency material distribution model with uncertain roads.Changes in road traffic conditions caused by disasters,resulting in road congestion and damage,which lead to changes in the road network environment,use the degree of road network damage and the double randomness of road damage to establish an impact model of uncertain road damage on distribution.Based on the two-stage analysis method of the road network distribution route,basic data analysis and nonlinear fitting regression analysis are carried out on the distribution cost,road network space accessibility and distribution efficiency.Through this model,it is concluded that there are regularities in the distribution cost of emergency materials,the spatial accessibility of the road network and the distribution efficiency under the changing environment of the road network.Through this research,the most suitable delivery route and delivery time can be selected to maximize delivery efficiency and reduce losses after emergencies occur.This research can provide a better traffic control method for emergency logistics traffic organization considering the temporal and spatial changes of the road network environment under the actual emergency situation.Solve problems such as insufficient traffic management strategies and emergency plans,and imperfect traffic organization,so as to avoid serious casualties and property losses.At the same time,it can formulate contingency plans for emergency management departments,provide better methods for responding to emergencies,and improve emergency management capabilities in response to emergencies.Realize the real needs of overall development and safety,and guaranteeing the safety of people’s lives and property.