Research On Urban Road Traffic State Evaluation

In recent years,with the continuous development of social economy,the number of motor vehicles has increased year by year,people's travel demand has increased.Due to the restrictions of urban conditions,the construction of road facilities is slow,resulting in serious urban traffic problems.Therefore,how to make use of the existing urban road resources to maximize social benefits,it is necessary to comprehensive evaluation of urban road traffic status,to provide the public with easy to understand the road information,for traffic managers to provide a scientific basis for decision-making.This paper makes a comprehensive analysis and research on the state of urban road traffic from three levels of intersection,road section and road network.The main tasks are as follows:On the basis of consulting a large number of related documents on urban road traffic state,the paper summarizes the evaluation index of traffic state,the discrimination method of traffic state and the evaluation grade of traffic state,and formulates the design principles of the index system.The index system of urban road traffic condition is established by selecting intersection index,road link index and road network index,and the comprehensive evaluation of urban road traffic state is carried out according to the index system.Firstly,the paper evaluates the traffic state of intersection,analyzes the problems existing in the existing evaluation index of intersection,and finds out that the evaluation of single index is not comprehensive and the overall evaluation of intersection can not show the detailed information of intersection.Finally,considering the parameters of intersection,three indexes of intersection saturation,average delay and queue length are selected to establish a multi-index evaluation model,which makes the evaluation more objective and reasonable.The unbalanced index model is established by selecting the average delay of each inlet direction of intersection to characterize the degree of imbalance in each direction of intersection.A comprehensive evaluation model of intersection is established by synthesizing two indexes,and the feasibility of the model is verified by simulation.Then the real-time traffic state of the road is analyzed by clustering algorithm.According to the fuzziness of traffic state,the fuzzy C-means clustering algorithm is selected,and the existing problems of the clustering algorithm are analyzed.The genetic algorithm is used to improve the clustering algorithm.The average travel speed,delay and saturation index,which can represent the running state of road section,are calculated by using the data of the bayonet.The index parameters are clustered by a large number of historical data,and the traffic state is divided into five categories.The real-time state is judged according to the partition result.Finally,based on the study of the traffic state evaluation of intersection and road sections,the road network running state function with the basic parameters of intersection saturation and average travel speed is established.The geographical location of intersection and section in the road network,traffic volume and other factors determine the degree of its impact on the road network operation state,comprehensive consideration of a variety of factors to determine the weight of intersection and section respectively.The effectiveness of the state function for road network traffic condition evaluation is verified by simulation.