Research On The Signal Control Method Of Roundabouts With Considering Traffic Emission

In recent years,with the rapid growth of motor vehicle ownership and the rapid development of automobile industry,the traffic congestion and urban environmental problems caused by vehicle exhaust emissions have also attracted people’s attention.Especially at the roundabout,a large number of vehicles gathered in the circulatory roadway of the intersection,the phenomenon of vehicles weaving into the circulatory roadway is obvious,the vehicles queue up and wait in line,resulting in the reduction of traffic operation efficiency and the increase of traffic emissions,which is detrimental to traffic flow and urban environmental protection.In view of this kind of problem,Chinese and foreign scholars have introduced the concept of traffic emission control into urban intersection signal control scheme,and achieved research findings.However,most of the existing achievements are aimed at the study of ordinary intersections.There are few studies on signal control methods of roundabout considering traffic emissions.This paper takes the roundabout as the research object.Firstly,we took the average vehicle delay and traffic flow at the intersection as the index,the traffic state of the roundabout is distinguished based on K-means algorithm,and on the basis of the traffic state analysis,the signal control setting conditions of the roundabout are proposed.Secondly,based on the VT-micro model of traffic emission,we established the computational model of Carbon monoxide and Nitrogen oxides at the roundabout.Finally,on the basis of intersection phase sequence designing and signal cycle calculating,in order to reduce traffic emissions and vehicle delay as the goals,the adaptive traffic signal control method of four branch roundabout based on model predictive control was proposed to optimize the traffic signal control parameters of roundabout,so as to optimize both traffic operation and environmental ecology.The experimental results showed that the adaptive control method of roundabout proposed in this paper can find a balance between reducing traffic emissions and vehicle delay,and realize the collaborative optimization of the two,which has a certain theoretical and practical significance.