A Research Of Forecasting Method For Through Traffic Demand In TIA

Through traffic demand forecasting is the important part of the background traffic demandforecasting. It is the vital link during the TIA of construction project. Its accuracy affectsdirectly the results’ reliability and correctness of TIA. At the moment, the percentage ofthrough traffic demands is obtained by experience. There seldom have quantitative methods.Researches about it have not been conducted systematically. The article has carried onresearches about the forecasting for through traffic demands on the bases of large amount ofmeasured data. The solution provides the theoretical basis and data for the background trafficdemand forecast in the process of traffic impact analysis of construction project, and perfectsthe methods of traffic impact analysis, which improves the reliability of the result about thetraffic impact analysis of construction project.10urban streets have been invested by this research. The total length is48.15km. Thereinclude6urban expressways,6urban main roads,8urban minor roads and117crossroads.491328cars have been matched with the method of license plate recognition.The solution that through traffic demands are influenced by the level, length, V/C of theroad and the type of interchanges has been fund by the research. The structural relationshipsamong through traffic demands and the four factors with the method of Factor of Analysishave been got. The level and length of the road are main factors. The minor factors are V/C ofthe road and the type of interchanges.According to the measured data, the relational models between the percentage of throughtraffic demands and the level, length, V/C of the road and the type of interchanges have beenconstructed. Then the relationships between the percentage of through traffic demands and thelength of road under the condition of different road levels have been obtained and themodified models about V/C of the road and the type of interchanges which affect thepercentage of through traffic demands have been give. At last, the suggested values were putforward.The research suggests: the percentages of through traffic demands on different road levelsare different in the background traffic demand forecasting of TIA. The expressways’ are thelargest, the main roads’ are smaller and the minor roads’ are smallest. There exists inverseproportion relationship between the percentages of through traffic demands and the length ofroad. With the length increase, the percentages decrease. There exists direct proportionrelationship between the percentages of through traffic demands and the V/C of road. As the value of V/C increasing, the percentages are larger. The interchanges have the most impact onthe percentages of through traffic demands. The separate interchanges have the minimalimpact.