Study On Highway Network Traffic Conditions Evaluation Under Abnormal Events

Transportation has played a fundamental and guiding role in the construction ofmodernization in our country. At the same time, the rapid development of highwayindustry has become an important part of transportation，which is contributing a lot tomodernization construction of our country. But as the saying goes: people andtragedies will descend, the month there is short of a round, with the trend of economicglobalization, the world’s population is continuing to grow, excessive request ofhuman for natural, earthquakes, floods, landslides and, more recently, people paymore attention on fog weather and natural disasters, man-made disasters such asterrorist attacks, causing great casualties and property losses to the human socialproduction and life, highway system the so called "life system" is suffering anunprecedented test.Various countries in the world have a lot of achievements on the study ofhighway system. However, compared with the normal events of highway systemconditions, the traffic conditions of highway network after abnormal events is facinggreat changes, while the researches at home and abroad are very shallow, lacking ofresources. How to let the builders and the mangers grasp the real-time traffic statusafter the incidents, and how to let them make good judgments about the future state oftraffic over a period? I study the idea like following:First of all, This paper first clarify the meaning of the highway network trafficconditions, and do the research about the characteristics of highway network trafficconditions under normal events traffic from traffic flow characteristics, the servicelevel of highway system, and Road features. Referring topics for the definition of"abnormal events", I describe different abnormal events for highway system, theinfluence of the traffic flow and the effects on the service level of road network. Theanalysis and researches show that abnormal events under the overall networkoperation condition changes. Index evaluation system can’t trial now, leading toabnormal events below the index system of research.User demands analysis of highway network traffic conditions under abnormal events. Principal users in this paper are divided into traffic management and controldepartment, road users. With fully understand of different needs of different users, Ievaluate and design principles about standard system under abnormal event, the paperproposes a new method of the multi-target appraisal, that is the evaluation method of"first running state classification and then run trend analysis". With the considerationof the access of the traffic parameter, I select the traffic parameter classified, anddetermine the threshold of four types of basic traffic index under abnormal events.Finally I build the index system of highway network traffic conditions underabnormal events.This paper divide the abnormal events into active and passive two types whichdepends on the different effects, and do the quantitative indicators based on differentevents. I constructs two different kinds of evaluation methods from the indexstandardization and construction of subordinating degree function. Finally simulatingthe network traffic by paramics simulation, fully shows that the constructedevaluation index system is scientific and accurate.