A noise is defined as any unwanted sound that is created by movement of an object. Any type of noise is a pollutant and is hazardous to human health and hearing. Hearing impairments, which are found to be very common these days, are a result of the heavy noise produced by traffic, vehicle engines, exhaust machines and tires. Various strategies are implemented for the control of the intensity of the highway traffic noises. One of these strategies is Highway noise barriers.
What are Noise Barriers?
A highway noise barrier, also called as sound wall, sound berm, sound barrier or acoustical barrier is a solid obstruction constructed from earth mounds, concrete, masonry, wood, metal, and similar materials. This barrier is placed between the highway and the homes that reduces the frequency and loudness of highway noise. These barriers reduce overall noise levels by 5 to 10 Db. It is useful in reducing the noise levels for the people living next to highways. Depending on the material used for the construction highway noise barriers are most effective within 200 feet of a highway.
Working mechanism of Noise Barriers
Noise barriers reduce the noise which enters a community from a highway. Absorption, reflection, or forcing the sound to take a longer path over and around the barrier is the appropriate mechanism through which noise is reduced. Sound waves travel out in all directions from vehicles on the highways and the intensity decreases as it travels away from the source.
When the sound waves encounter an obstacle or barrier, they t bounce back if the surface is reflective or get absorbed into the cavities if the surface is porous. This is the process known as noise absorption. If the barrier is tall enough to break the line of sight from highway to community it can reduce up to 5 decibel of noise level.
Strategies for the adaptation of noise barriers
Various strategies are used for the adapting the noise barriers. Tree plantation, along with other vegetations, according to the ecological surroundings of the particular place is an effective strategy of noise barrier adaptation. It is a natural and less expensive strategy for noise reduction. Other strategy is to bring out lines and forms of landscape or town to the roadside, reducing the noise to certain extent.
To make noise barriers stand out stand as a striking and visible addition to its surroundings, through an effective selection of colors and forms is also a strategically positive step in the path of noise reduction along the highways.
Disadvantages of Noise Barriers
Certain disadvantages were found to be associated with the use of Noise barriers like the topographic beauty of the surrounding area is often found to be disturbed and blocked. Ecological niche of certain flora and fauna get degraded due to construction of the noise barriers. It causes great economic impacts due to the construction cost and maintenance of the barrier. Drainage system is also found be damaged due to barrier construction.
Although with some disadvantages, noise barriers are still an effective way to combat sound pollution and its dangerous effects on all the living beings including man and animals.