Gis-based Traffic Flow Model Develpmention And Its Applied Research

The traffic flow model uses diagrams to describe flow-speed-density relationships.It is a basic study of traffic flow characteristics and a mathematical tool for exploring traffic laws and formulating traffic control measures.With the increase in car ownership,it is difficult to solve the issues of traffic congestion and pollution by simply relying on infrastructure construction.On the basis of geographic information system,using big data mining technology to analyze the basic laws of traffic flow,and to conduct a diversified evaluation of traffic volume,has become the key to improve the performance and efficiency of road networks and accelerate the development of intelligent transportation technology.However,due to the limitation of traffic data collection techniques and analysis methods,the study of current traffic flow models mostly focuses on typical segments of highway and expressway.Based on the above background,traffic flow models at different grade roads are constructed and model application research is carried out.The research work is as follows:(1)Drawing on the previous research results of traffic flow models and traffic flow parameters,the basic form and application scope of classic traffic flow models are studied in detail.The modeling method is to at first determine the general shape of the model based on the measured traffic flow data,then use multiple classic traffic flow models to linearly fit the speed-density parameter relationship,and finally select the optimal model.(2)Selecting Underwood model as the base model,as well as the optimal density and capacity are calibrated.In order to optimize the traffic flow model and make up for the shortcomings that the model calculation traffic flow is not consistent with the actual situation due to the unstable speed,the minimum flow of each grade of roads is corrected,and the traffic flow of highway and expressways in the early morning and at night is adjusted.Finally,the measured data of typical roads is selected,and the applicability of road traffic flow models of various levels is judged by numerical analysis.(3)The research obtains the traffic flow information of the entire road network according to the big data analysis process,and analyzes the differences in coverage of roads at different levels.Secondly,the time-varying laws of traffic flow and speed are discussed,and the occurrence time and total flow ratio of morning and evening peaks are further analyzed.Based on the information of vehicle hours traveled in each speed section,the difference analysis of the speed distribution characteristics of each grade of roads is completed,and the low,medium and high speed section weight coefficients are obtained.(4)The specific application of the traffic flow model is studied,and the effects of holidays,seasonal changes on the characteristics of traffic flow are analyzed.According to the above-mentioned influencing factors,the change rules of traffic flow information such as traffic flow,speed,and vehicle hours traveled are summarized to provide a reference basis for more accurate traffic volume prediction.