Research On Traffic Flow Modeling And Emission Of Urban Work Zone

In recent years,new traffic facilities have been built up in China,and construction phenomena on freeway and urban trunk line is frequent.Especially in urban roads,a large number of work zones appeared on signalized intersections and links.Work zones reduces the traffic efficiency at signalized intersections and links,resulting in a large number of queues,which increases vehicle energy consumption and exhaust emissions that causes serious pollution to the atmosphere.Due to the obvious heterogeneity of vehicles on the urban roads and the change of road characteristics after the establishment of the work zone,the traffic flow modeling and emission research becomes more difficult.Although a lot of research has been carried out in the work zones,most of which is concentrated on the expressway,and the research on the urban road work zone is relatively rare.Because of the obvious heterogeneity of urban road vehicles,it is difficult to find a unified rule for cars,large vehicles,pedestrians and non-motor vehicles.Besides,there are characteristics of intersections or links in the work zones,such as no-lane division and irregular driving boundaries.Some traditional traffic flow models do not apply to this complex traffic scenario.This paper mainly focuses on the signalized intersection work zone and link work zone of urban road.By analyzing different vehicle driving behaviors,two traffic flow models are established.Then the actual traffic flow data are used to calibrate and verify the models.The microscopic traffic flow model and the microscopic emission model CMEM were coupled.Referring to the formula of fuel rate and CO₂ gas emission rate in CMEM model,the relationship between vehicle fuel rate and CO₂ emission rate and speed,acceleration and other variables were given This paper analysis the traffic,the fuel flow rate of the motor vehicle and CO² emission rates by changing the value of some factors,these factors include:vehicle speed,the proportion of large vehicles,arrival rate of non-motor vehicle,the size and position of work zones etc..Through the research,we get the following conclusions:The width of the central boundary zone from the upper boundary of the work zone to the intersection of the intersection is the most significant influence on the traffic flow and the average traffic speed of the signalized intersection;the proportion of the large vehicle and the non-motor vehicle have a certain degree of influence on the traffic flow.The width of work zone,the proportion of large vehicles and vehicle speed limit have a significant impact on the traffic flow and average speed of link work zone;especially the width of the work zone in this simulation platform if reaches a certain value,which will make the average vehicle speed reduces about 1/3 and reduces by about 85%of the number of vehicles;Coupling the microscopic traffic flow model with the CMEM model,we can see that with the increase of relative factors,the fuel consumption rate and CO₂ emission rate of vehicles almost increase or decrease.Among them,with the increase of vehicle speed limit value V_max,the change of vehicle fuel rate and CO₂ emission rate has two times function.It decreases first and then increases.Therefore,if the vehicle speed limit can be reasonably regulated under actual conditions,it can make vehicle energy consumption and emission reach a lower value.