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Assessment of traffic noise pollution in developing countries is complex due to heterogeneity in traffic conditions like traffic volume, road width, honking, etc. To analyze the impact of such variables, a research study was carried out on a national highway passing from an urban agglomeration. Traffic volume and noise levels (L₁₀, L_min, L_max, L_eq and L₉₀) were measured during morning and evening peak hours. Contribution of noise by individual vehicle was estimated using passenger car noise unit. Extent of noise pollution and impact of noisy vehicles were estimated using noise pollution level and traffic noise index, respectively. Noise levels were observed to be above the prescribed Indian and International standards. As per audio spectrum analysis of traffic noise, honking contributed an additional 3–4 dB(A) noise. Based on data analysis, a positive relationship was observed between noise levels and honking while negative correlation was observed between noise levels and road width. The study suggests that proper monitoring and analysis of traffic data is required for better planning of noise abatement measures.

Geographical information system (GIS)-based noise simulation software (N-GNOIS) has been developed to simulate the noise scenario due to point and mobile sources considering the impact of geographical features and meteorological parameters. These have been addressed in the software through attenuation modules of atmosphere, vegetation and barrier. N-GNOIS is a user friendly, platform-independent and open geospatial consortia (OGC) compliant software. It has been developed using open source technology (QGIS) and open source language (Python). N-GNOIS has unique features like cumulative impact of point and mobile sources, building structure and honking due to traffic. Honking is the most common phenomenon in developing countries and is frequently observed on any type of roads. N-GNOIS also helps in designing physical barrier and vegetation cover to check the propagation of noise and acts as a decision making tool for planning and management of noise component in environmental impact assessment (EIA) studies.

Traffic noise barriers are one of the most important ways of environmental noise pollution control. Profiled barriers are one of the most successful noise control screens. A simple mathematical model representation of the zones behind rigid and absorbent barriers with the highest insertion loss using the destructive effect of the indirect path via barrier image is introduced. The results are compared with the results of a verified two-dimensional (2D) BEM in a wide field behind those barriers. Field measurements for the model near a highway in a megacity were also tested. A very good agreement between the results has been achieved. In this method, effective height is used for any different profile barrier. Since the highway dominant noise frequency was found to be at 125 Hz 1/3-octave band center frequency, the presented model in this study showed that the best place for installing a T-shaped barrier is 10.5m from the target receiver. The introduced model is very simple and fast and could be used for choosing the best location of profiled barriers to achieve the highest performance with no additional cost.