Analysis and Evaluation of Urban Road Traffic Noise Pollution in Addis Ababa City

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Date

2019-06

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Addis Ababa University

Abstract

Addis Ababa city like most of the cities of developing countries are, facing serious environmental traffic noise pollution problem, due to the increasing at an alarming rate of motor vehicles, the expansion of the road network, and poor urban planning. This study is directed to examine the status of highway traffic noise level at different landuse areas along different road class moreover, relationship between noise level and traffic flow is developed. In this study, four main categories of the traffic route and land use are established. Traffic noise levels and traffic volume were conducted 9 times at each 41 selected spots on different days of weeks across four various land use areas of the city for 15 minutes with 3 readings per each period of the day time; morning (7AM-10AM), afternoon (11AM-3PM) and evening (4 Pm-7PM). Statistical analysis of daytime traffic noise in the city was carried out and results are presented in terms of average percentage of exceeded noise level: L10, L50 and L90. Main noise descriptors viz. Equivalent continuous noise level (Leq), traffic noise index (TNI), noise pollution level (LNP) and noise climate (NC) are determined and discussed for each spot per road category and land use. Results of this study indicated that the highest range of Leq 77.2 to 80.7 dBA was observed in industrial zone followed by 75.1 dBA-80.1 dBA in commercial zones, 71.7 - 80.0 dBA in sensitive zones, and 70.0 - 79.1 dBA in residential areas. Observed Leq (dBA), at all measurement points exceeds national and international standard limit values by 2.2 to 25.0 dB (A) and 12.2 to 35.0 dBA, respectively. ANOVA test shows that there is a significant difference (P < 0.05) in noise pollution levels and equivalent noise level in established land use areas. Also, result parameters F-test statistics implies there is no significant difference between overall morning, afternoon, evening time traffic noise level in the city as F calculated (0.005) < F critical (3.07). A linear regression analysis performed between the Leq and logarithm of total traffic volume (log Q) produced a coefficient of determination r of 0.851. A multi regression analysis carried out between the Leq and two classes of traffic vehicle types resulted in a correlation coefficient of 0.7502. Results of this study clearly revealed that total traffic volume and number of heavy transport vehicles are the most significant factors of cities traffic noise pollution. Spearman rank correlation coefficients with value of -0.812 again proved that the classification of urban street noise as a meaning of the road hierarchy is an appropriate part of the design of studies of urban noise caused by traffic. In order to reduce alarming condition traffic induced noise levels within the city, both technical actions and nontechnical approaches were also presented.

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Keywords

Urban Road Traffic Noise, Noise pollution in Addis Ababa City, Evaluation, Analysis

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