Analysis And Comprehensive Evaluation On Traffic Pollution At Urban Road Intersection

With people's concern about the traffic pollution day by day, the green or environmentaltraffic system has already become an inevitable request of the development of modern city. Asimportant node of urban road network, road intersection is actually a "bottleneck" of smoothtraffic. The traffic capacity of road intersection is lower than urban road section, and trafficpollution of road intersection seems to be particularly an important problem. Based onsummarizing and consulting relevant research at home and abroad, the thesis systematically hasanalyzed the pollutants diffusion rule of motor vehicle at intersection, the average emissions of thepollutants per hour and the comprehensive traffic quality of intersection.The thesis has analyzed the status in quo of urban traffic vehicle emission pollution, and hasconfirmed HC, CO, and NOx as evaluation factors of air pollution. A series of models of vehicleemission factor are summarized and analyzed, and MOBILE6.2model and its analysis softwarewere selected to calculate the motor vehicle emission factors in Changchun city. The Parameters inmodel such as REG, DIST,MAR, VMTFRACTION, AVERAGESPEED, SULFURCONTENT,I/M, FUEL RVP, ABSOLUTE HUMIDITY, MIN/MAX TEMP, etc were modified, Therefore thekinds of motor vehicle emission factors in Changchun were calculated. By mean of conicestimation method, the motor vehicle emission factors fitted model which takes the average speedof motor vehicle as independent variable was determined.For the research of motor vehicle pollutants diffusion rule at intersection, considering thesignal controlling effect on pollutants diffusion and comprehensively analyzing the vehiclesoperation (or moving) features at intersection, two types of emission source intension, that is greenlight emission source intension and red light emission source intension, were identified, and theweighted sum of the two emission source intension was calculated for average emission sourceintension by the matched time of signal. Combined with the CALINE4line source dispersionmodel, intersection emission diffusion model was constructed based on the signal cycle.Simulating mass concentration distribution of CO and NOx near intersection of Renmin Avenueand Ziyou road, the diffusion model to be used to study on pollutant dispersion distribution (or law)was validated.During studying on the average pollutants emissions per hour at road intersection, the authorthought that the total pollutants emission at road intersection is the sum of constant speed vehicleemissions and the additional emissions by vehicle delay. Based on analysis of traffic flowcharacteristics and the transport parameters determined, the four emission models, which areconstant speed pollutant emissions, additional emissions by stopping, addition emission byslowing down, and additional emissions by idling respectively, were established. The models wereapplied to simulate the total pollutants emission at typical intersection in Changchun city. Theresults show that the models can provide a theoretical basis for the total pollutants emission inurban regional network road.Based on the intersection characters and influence effect factors of traffic quality, the comprehensive traffic quality evaluating system at intersection was established. With the help offormer researches, the author applied Analytical Hierarchy Process (AHP) to construct judgmentmatrix, sort level single and the total ranking of the various influencing factors, to ascertain theevaluation index weight. And multi-hierarchical grey evaluation method was mentioned toevaluate5typical intersections in Changchun city. The methods can analysis the traffic safety ofdifferent ways or different sections of the same road. Visually comparison of the pros and cons ofevaluation object and identify weak links were targeted to improve and enhance the quality ofservice about urban road intersection.