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