Abstract: In order to explore temporal and spatial variation rules of traffic load on a road network in a burst environment, the production-dissipation process of emergency was studied by using the scenario analysis method. Then, the road network was divided into 2 sections: normal link set and incident link set. A dynamic traffic assignment model was built for the former by using the discrete method. A approximate model of traffic load was built by using the Logistic curve with 3 parameters for the latter. The "reverse"solving strategy was used to transform the network into a reactive discrete control system. The Lan-Filler decomposition algorithm was adopted for finding the dynamic solution. The result shows that road network vulnerability index varies with the emergency's production-dissipation process dynamically, that compared with the traditional methods, using the dynamic vulnerability identification model based on Logistic curve can ensure road network's topology structure unchanged and correctly identify each link's vulnerability on road network.

Key words: burst environment, road network, dynamic vulnerability, Logistic curve, Lan-Filler decomposition algorithm