A three-dimensional noise mapping study for heterogeneous traffic conditions

Characteristics of noise in terms of frequency, noise level, vary considerably with respect to heterogeneous traffic. Urban traffic noise characteristics in the cities of a like India are slightly varied in the sense that the composition of the traffic is heterogeneous. A heterogeneous traffic stream composes of vehicles having different speeds, sizes, and operating characteristics. While studying the feasibility of noise reduction in some of the areas around a heterogeneous traffic stream, a three-dimensional (3-D) noise mapping study has been attempted with the help of Arc GIS, Arc Scene along with field measurements. The methodology involves to build 3-D noise models to analyze the 3-D occurrence of noise pollution. Specifically in this work a 3-D acoustical model has been developed for a local area. Subsequently, the observation points around the buildings have been determined and the noise levels have been calculated using the authors' regression model. The noise mapping parameters such as Ld, LN, and Lden have been calculated incorporating the geometrical features of the roads and varying heights of the buildings, heterogeneity, and prominent honking conditions. This work leads to the prediction of noise levels in front of building facades both in horizontal and vertical directions.