Study On The Models Of Urban Expressway Traffic Flow With Consideration Of Lane-changing Behavior

As the highest level traffic facility in urban traffic system,the city expressway plays an important role in achieving rapid mobility of the urban traffic.The meaning is self-evident to establish urban expressway traffic flow model accurately portraying the characteristics of urban expressway traffic flow,which is a basic research about city expressway planning,design and operational management.Although the city expressway has many characteristics of freeway,its dense entrance distinguishes from the conventional freeway.A lot of lane-changing behaviors in weaving areas have significant effect on traffic flow in city expressway.Thus,unlike the freeway traffic flow modeling,the impact of behavior changing lanes in the urban expressway traffic flow modeling cannot be ignored.Since the observation is difficult,people began to study after emergence of the aerial image technology(1980s).Till now,the most studies of the lane-changing behavior effect in traffic flow focus on the fundamental diagram method.The proposed models were rather complex,and difficult to estimate parameters,and they can only reflect the correspondence between the singlet states of parameters of traffic flow.The three-phase model of traffic flow theory proposed in recent years could show the parameters relationships in multi-state corresponding multi-state,but not yet consider the impact of the lane-changing behavior.Therefore,the existing models are difficult to describe accurately the traffic flow in city expressway which has a large number of lane changes.This dissertation studied the third-ring road in Chengdu which has tipical characteristics of city expressway,used data driven modeling method,collected and analyzed the data from 9 sections and constructed four-phase flow&lane-changing,four-phase velocity&lane-changing,four-phase density&lane-changing,and four-phase traffic flow models,in which lane-changing behavior was considered.Compared with lane-changing traffic flow model which based on foundamental diagram and three-phase traffic flow model.the proposed model could better dicribe the roads which have numbers of lane changes.The novelty of the dissertation is in following areas:(1)We first proposed multi-level block background model(Patent No.201510955922.2(make public))(3.1.1)in this dissertation.The model resolved the problems with missing and false objects.Compared with LBP,CSLBP and CB models,the proposed model extracts foreground objects better.Based on the model,we developed a video-based recognition city expressway traffic synchronous data acquisition software(software copyright ID:2016SR085062).The software enables flow,speed,density,and the number of data transfer channel synchronous acquisition,and provides a reliable data entry for the establishment of changing lanes behavior model of city expressway traffic flow.(2)We utilized regress and cluster methods to propose four phase flow&lane-changing(4.3),four phase velocity&lane-changing(4.4)and four phase density&lane-changing models(4.5),respectively,which describe the lane-changing behavior impact on flow,velocity and density.Among them,the four-phase density&lane-changing model makes up for the shortage of research in this area.Four-phase flow&lane-changing and four-phase speed&lane-changing models reveal that traffic and change lanes,speed and change lanes were polymorphic corresponding relationship,rather than studies have revealed a linear relationship between the singlet and curves.Measured data show that the four-phase model constructed in this paper is closer to the actual traffic flow.(3)We used measured data and cluster method to describe the lane-changing behaviors impact on the 2D space with flow&density,flow&velocity,and velocity&density,that is,a model considering the lane-changing behavior of four-phase flow&density model(5.3),four-phase flow&velocity model(5.4)and four-phase velocity&density model(5.5).The three models construct four-phase traffic flow model which consider lane-changing behavior(5.6).Compared with the lane-changing traffic flow model which based on fundamental diagram and three-phase traffic flow model,the proposed models could better describe the city expressway with the numbers of lane changes(5.7).