Research On Traffic Flow Simulation And Evaluation Of Basic Freeway Sections

With the enlargement of the scale of the freeway network system, the analytical work to its operation conditions will be more and more important .Taking operation conditions of Jiangsu Province as an example, a lot of new problems appear:The road conditions of most freeways decay; Various kinds of different kinds of vehicle,different running speed, all of these cause the traffic flow to be unstable and the capacity drop;The traffic jam appears in some specific freeway section;etc.The operation conditions of traffic flow have already begun to cause the extensive concern of the circle of domestic and international highway on the expressway.First of all, the author analysed the characteristic of traffic flow on the basic segment of freeway,such as:the space-time distribution of traffic volume,vehicle's headway distribution characteristic ,etc. And analysed the basic state of vehicle in running: free driving;follow run;lane changing and its influence.Secondly, set up a simulation model of basic segment of freeway,including road model,driver-vehicle model,running model and result model. And the running model is the key part,which including depart model,free driving model,following model and lane-changing model,etc. The author carry on research to the model of following run and lane changing especially, and ascertain the parameter of model, and have developed the corresponding simulation software.Thirdly, a series of simulation experiments was designed, According to the result data of experiments, analysed the characteristic of traffic flow,such as time mean speed,space mean speed,flow rate,average occupancy time of each vehicle,density,etc.Study the interreaction between every index ,and put forward the rational evaluation index system and corresponding evaluation criterion.Finally, analysed the goodness and shortness of various kinds of comprehensive evaluation methods , choose a appropriate method to evaluate the freeway operation conditions.