Traffic Situation Assessment Of Urban Road Under Emergencies

With the rapid development of economy and the improvement of people’s living standards, the city scale expands unceasingly and motor vehicle ownership increases quickly. Then the probability of urban road traffic emergent events will also increase.The occurrence of traffic emergent events will not only cause casualties and property losses, but also have a significant impact on the urban road network traffic. Therefore, it is in urgent need of research on traffic emergency management, how to do a good job for urban road traffic situation assessment under the emergency events according to the event site, feedback and extract information. In order to reduce the impact of traffic emergency events and losses, it also provide a basis for emergency department to respond quickly and make a correct decision.First, this paper introduce relevant theories of emergency events and the urban road traffic emergency events. It carried on the single factor traffic emergencies cause analysis, then, a model of the cause by coupling with three factors was built based on system engineering theory and accident cause theory.Second, it introduced the concepts and technology of situation assessment of military field into intelligent transportation field, and made a definition of urban road traffic incidents situation assessment. It builded a traffic emergency situation assessment research framework based on the functions of situation assessment model. The assessment process was divided into three stages:situational awareness, traffic situation forecast and traffic situation evaluation. Considering the influence factors of traffic situation, such as events factors, environmental factors, road network factors and operational factors, the factor index system and traffic situation index system were set up to make foundation for traffic situation forecast and traffic situation evaluation.Then, Bayesian network was introduced in the prediction of the traffic situation. Index of incident duration, for example, by determining the network node, Bayesian network topology structure and the conditional probability distribution, the traffic situation incident duration forecast model base on Bayesian network was builded, and a case analysis was carried out by GeNIe2.0software. Finally, this paper established the traffic situation evaluation model based on the method of fuzzy comprehensive evaluation, and demonstrated the feasibility and adaptability of the model with a case analysis.