Study On Analysis And Evaluation Of Road Traffic Pollution About Interchange

With people's concern about the traffic pollution day by day, the environment protection of traffic system has already become an inevitable request of the development of modern city. As important nodes of highway and urban road network, interchange's traffic pollution seems to be a particularly important problem. So it has very important theoretical significance and practical value to study the inner relationship between traffic pollution and geometry design conditions of the interchange, and to quantitatively evaluate traffic pollution of interchange design according to geometric design index of interchange. The thesis systematically analyzes the relationship between air pollution, traffic noise and the geometric design index of interchange based on summarizing and consulting relevant research at home and abroad.At first, the thesis studies the decomposed method of interchange from the starting of the demand of traffic pollution study. On the basis of analyzing the alighnment composing of circular curve unit and transition curve unit of left-turn and right-turn ramp, the typical left-turn ramp of the left-exit-and-left-entrance type, the left-exit-and-right-entrance type, right-exit-and-left-entrance type, right-exit-and-right- entrance type, circle type and right-turn ramp of oblique line type, single and compound curve type, reverse curve type, parallel type are chosen and the combined methods of the familiar three-leg interchange and four-leg interchange are studied. Since ramp is the key part of studying traffic pollution of interchange, the thesis starts with analyzing the change of vehicle travel speed when driving on the ramp, and then analyzes the impacts of ramps'slope and radius on vehicle speed. In the next place, on the principle of the vehicle pollutant emission and traffic noise energy accumulating gradually with the increased length of ramp, the thesis establishes the function between vehicle speed and the length of ramp, which settles the foundation of establishing relationship between pollutant emission, traffic noise energy and the length of ramps using the vehicle speed as the link.For studying the air pollution of interchange, carbon monoxide (CO), hydrocarbon (HC ) and nitrogen oxide (NOx ) are chosen as the assessment factors. The thesis divides the vehicle into five types such as light-duty vehicle, medium-duty vehicle, heavt-duty vehicle, oversize vehicle and motorcycle. Besides, it provides the fitting relationship between emission factors of vehicular pollutants of the five vehicle types, three kinds of pollutant emission and vehicle speed, on the basis of summarizing, generalizing and consulting the research of the relationship between emission factors of vehicular pollutants and speed at home and abroad. Through the functional relationship between the speed and length of ramp, the functional relationship between the emission factors of vehicular pollutants and the length of ramp when accelerated traveling on the ramp is established, and the calculation formulae of emission of vehicular pollutant correspondent to the length of ramp is given through the integral operation, on the basis of which, through calculating the total amount of pollution of ramp and the main road, the whole amount of pollution of interchange is gotten. The thesis also presents the concept of the equivalent air pollution and provides the calculation formula of volume equivalent air pollution of interchange and extent equivalent air pollution of arterial road, left-turn ramp and right-turn ramp.For studying the traffic noise pollution of interchange, the thesis chooses the equivalent sound level as the assessment index and defines the concepts and calculation method of relative equivalent energy. On the basis of summarizing, generalizing and consulting the research of the relationship between noise level and speed at home and abroad, it provides the fitting relationship between relative equivalent energy and vehicle speed, and establishes the functional relationship between relative equivalent energy and the length of ramps. The total relative equivalent energy of vehicle correspondent to the length of ramp is given through the integral operation, and then, equivalent sound level of vehicle is presented, on the basis of which, through overlapping calculating equivalent sound level of vehicle on the ramp and the main road, the whole equivalent sound level of interchange is presented. The thesis also proposes the concept of the equivalent noise pollution and provides the calculation formula of volume equivalent noise pollution of interchange and extent equivalent noise pollution of main road, left-turn ramp and right-turn ramp.The thesis chooses fifteen indexes of three categories including equivalent air pollution, equivalent noise pollution and reduction coefficient. On the basis of comparing the methods of fuzzy synthetic evaluation,grey relevancy analyzing evaluation,hierarchical level assessment,neural network evaluation,matter element analysis evaluation and so on, matter element analysis method is chosen to evaluate the traffic pollution of the design of interchange. Through determining expected evaluation matter element, traditional matter element matrix and matter element matrix, calculating each index weighting, relating function and the subjection degree, and comprehensive evaluating the schemes, the thesis establishes traffic pollution evaluation model of interchange based on matter element analysis, and chooses the minimum traffic pollution plan from lots of design schemes.The main research results of the thesis are: proposing the decomposed method of left-turn and right-turn ramp and alinghment unit of interchange based on traffic pollution analysis; analyzing the course of speed change on the ramp and the influence factors, and establishing the functional relationship between speed and the length of ramps; establishing the functional relationship between emission factors of vehicular pollutants and the length of the ramp when traveling on ramps, and deducing the calculation formulae of emission of vehicular pollutants and the total emission of interchange pollutants; Proposing the concepts and calculation formulae of volume equivalent air pollution of interchange and extent equivalent air pollution of arterial road, left-turn ramp and right-turn ramp; presenting the concepts and calculation formulae of relative equivalent energy, establishing the functional relationship between the relative equivalent energy and the length of ramps, and deducing the calculation formulae of equivalent sound level of vehicle and of the whole interchange; Proposing the concepts and calculation formulae of volume equivalent noise pollution of interchange and extent equivalent air pollution of main road, left-turn ramp and right-turn ramp; Presenting traffic pollution evaluation model of interchange based on matter element analysis.