Analysis On Characteristics Of Traffic Flow On The Urban Expressway

The analysis of traffic flow characteristic is an important part of traffic flow theory.Studying deeply expressway traffic running situation and the change of the traffic flow parameters, the related law of traffic flow parameters is summarized, providing theoretical guidance for scientific control the traffic flow of expressway and travelling.Combined with the investigation traffic flow data of the urban expressway in Beijing, the study analyze traffic flow characteristic based on driver behavior characteristics,specific content as follows:1、Analyzing expressway traffic flow parameters’variation characteristics, traffic volume, speed, density (because density is difficult to measure, so the time to share is used instead) and building their relationship model. FCM is used to perform the cluster to obtain the division results of traffic conditions.2、Considering the different characteristics of drivers, drivers can be divided into aggressive and careful drivers. Aggressive drivers tend to run at high speed, less braking, and keep smaller space between vehicles.However careful drivers tend to run at low speed, and keep larger space between vehicles. Based on the above driver characteristics, following state is divided into strong car following and weak car following two states.3、The analysis of car following is generally studied from two aspects, one is car following model, another is how to determine car following status. On the basis of the observed traffic flow data, the relationship between vehicles running characteristics and headway is deep analyzed, and then the method that using change rule of absolute value of relative velocity when headway changes to quantitatively determine the vehicle running state is put forward.4、Using the gaussian mixture model to validate assumptions that strong car following and weak car following exist. Based on the characteristics of strong and weak car following, the headway mixed distribution model is propsoed, further compared with other common used headway models.5、Using the the standard deviation of speed,difference between V85and V15and absolute value of adjacent velocity difference to analyze characteristics of speed dispersion.