A Statistical Analysis of Traffic Flow Characteristics of Multilane Highways in Baghdad City, Part B: Traffic Noise Levels

Road traffic noise is a function of basic traffic element (flow, speed, density) and percentage of heavy vehicles. The recognition of traffic noise as a one of the main sources of environmental pollution has led to the development of statistical models that enable the prediction of traffic noise level from fundamental variables of basic traffic element. The main objective of this research is finding out the effects of these elements on traffic noise levels for multilane highways in Baghdad city. Data has been collected throughout an extensive field survey on twenty selected sections in the study area. Noise levels were measured by using sound level meter in five stations in each selected road and the noise level reading was taken at each ten seconds, the reading of sound level meter was recorded directly, then the noise levels were determined ( L10, L50, L90, Leq). Statistical technique is applied to analyze the collected data by the aids of computer program packages in order to present the best model to describe the influence of flow, speed , density and percentage of trucks on traffic noise levels. The results of this study indicate that the second and third order equations are the best models that represent the effect of each traffic element on each traffic noise level in general, and especially on L16 noise level.