Noise pollution is a rapidly growing concern in Abuja’s urban areas due to traffic and construction activities. The increasing noise levels have become a source of discomfort for the public and community. When driving through the city center, one can observe that traffic noise is one of the most pervasive sources of noise pollution in the environment. However, historically, measures to reduce environmental noise have had a lower priority than those addressing air and groundwater pollution.
To address this problem, it is essential to determine whether there are ambient noise level standards in Nigeria that can determine specifications and levels for the prevention of air, water, and earth pollution. These standards are usually political or administrative settings, but international standards can also be used. In Abuja, as there are no heavy industries, traffic has become the major source of noise emissions. Recent surveys have reported noise peaks in the vicinity of 90 dBA at several urban locations and during different times of the day.
Several factors contribute to the high noise levels, including lack of periodic maintenance of the vehicle fleet, high frequency of acceleration/deceleration due to stop-and-go situations resulting from traffic congestion, low-quality, friction-inducing pavement surfaces, and excessive use of horns in traffic jams.
Noise is defined as unwanted sound that has the potential to disturb human or other activities. Extended exposure to elevated sound levels (90 dBA or more) can be injurious to people or other living organisms. In modern urban settings, transportation operations are major contributors to noise pollution. Noise is generated primarily by the engine and exhaust systems of vehicles, aerodynamic friction, and tire-pavement interaction. However, the most significant transportation-related problems are confined to transportation corridors as sound diminishes with distance away from the source.
The level of road traffic noise typically depends on three factors: traffic volume, traffic speed, and the percentage of heavy vehicles in the fleet. Heavier traffic volumes, higher speeds, and greater numbers of trucks amplify the loudness of traffic noise. Vehicle noise is a combination of noises produced by the engine, exhaust, and tires, and defective mufflers or other faulty equipment increase the loudness of traffic noise.
To address the noise pollution problem, it is essential that all major city centers in the country begin to perform and present a noise impact assessment at major intersections, particularly where a grade separation exists or is proposed. Field measurements should be conducted to define current noise exposure levels and calibrate a noise emission model. Simulations should be performed for several scenarios, including with and without grade separations. The assessment of the impact significance of noise emissions should then be conducted by comparing the predicted noise exposure levels with baseline noise levels and relevant noise exposure standards with the objective of optimizing the intersection management in terms of minimal noise impacts.
Moreover, it is crucial to explore the sensitivity of noise levels to changes in the geometric and operational setup of a typical intersection. Experts should be engaged to recommend and design an optimized efficiency of intersections to ensure a beneficial formulation of future transportation strategies.
Several techniques are available to reduce noise levels, including elevating or depressing the roadway, reducing traffic volume, decreasing traffic speed, using noise barriers, insulating nearby buildings, vegetating nearby terrain, acquiring buffer zones, using specific pavements, and managing traffic operations. However, most of these techniques achieve little reduction in noise levels if implemented separately. It is through the integration of several techniques that substantial noise reduction can be achieved. However, many strategies may not be practically feasible, such as depressing the highway, which may require high excavation costs, insulating buildings, which is not socially acceptable, using noise barriers, which may cause disamenity to nearby residents, vegetating nearby terrain, which requires the purchase of land, reducing traffic speed, which may incur socio-economic losses, and so on.
