Vehicle Routing Chosen For Emergency Relief Supplies On The Network Havoced By Earthquakes

The road transportation network of cities is an important part of the city system, which affects the entire city social and economic development. Road transport system in cities is a complex network system which is widely distributed. It can be easily damaged by the rubble of collapsed buildings and the efficiency of road network will reduced seriously. Devastating earthquake brings not only direct economic losses, but also causes indirect losses which bring inconvenience to rescue because of the damage of the traffic condition. So researching emergency vehicles path chosen right after the earthquake disaster is of great practical significance and practical value.First of all, by the analysis of earthquake disaster on the impact of road capacity, it is obtained that the most important factor that impacting the road capacity after earthquake is the rubble of collapsed buildings. So based on the model of the rubble distribution, considering the position relationship between buildings and roads, buildings and buildings as well as the features of roads, the changes of the roads'lane groups can be captured so that the assessed value of the capacity of each road can be obtained thus.Second, After the earthquake happened, vehicle routing for emergency relief supplies can be chosen from two aspects. One of that is vehicles path chosen before the trip. Under the condition of post-earthquake road network, the Logit SUE model is used to predict the demand of the traffic to obtain getting the travel time of each road. The vehicles path for emergency relief supplies chosen model before the trip is proposed considering the requirements of travel time and economic costs. The other is vehicles path chosen in the trip, according to the collected information on traffic congestion and disruption. Then this paper compares the integrated utility value of the bypass path and the one of the planned path to determine which one should be taken.At last, a network with certain structural properties is designed, also the structural properties after the earthquake can be given with the method of emergency assessment of post-earthquake roads'capacities. The traffic volume of each road is calculated by solving the traffic assignment model with Matlab. Then graph visiting algorithm is used to get the path of emergency vehicles before the trip. As the adjustment of paths on the trip, the travel time spent on the congested roads with various arrival time and various volume changed is discussed. As a result, the travel time spent on the path, with the congested roads included, and the utility value of the economic costs keep changing. That can be a basis of adjusting emergency vehicles. Thus the delay of vehicles will be reduced and emergency vehicles will get to the destinations frugally and rapidly.