In the world today, noise has become one of the most pervasive forms of environmental pollution.
Noise is everywhere. It affects our lives at home, at work and at play. Wherever people live there is noise. Noise, by definition, is any unwanted or excessive sound. It can be a nuisance, interfering with sleep, work or recreation, and in extreme situations, it can lead to anxiety, stress and other health problems.
As we know from our high school science classes, sound waves are created when an object moves or vibrates. When these waves reach our ears, they cause our eardrums to vibrate, sending signals to the brain that we interpret as sound. A measurement of the wave traveling through the air is used as an indication of the intensity of sound or its volume, and is described in terms of a scale called the decibel (dB). Noise measurements made by filtering high- and low-pitched sounds-approximating the way an average person hears sounds-is called the A-weighted level or dBA.
The dB(A) scale begins at zero, which represents the faintest sound that can be heard by humans with very good hearing. Conversations take place in the 50 dB(A) range and a chainsaw whines at about 100 dB(A). Normal highway traffic sounds rank about 75 dB(A) and jet airliners around 90 dB(A). For most people, discomfort starts in the 70 to 80 dB(A) range, with the threshold of pain around 140 dB(A). The Federal Highway Administration (FHWA) has chosen 67 decibels as the point where state and federal agencies must consider reducing the noise level.
Asphalt pavements provide a smooth, quiet, skid-resistant ride surface.
In the world today, noise has become one of the most pervasive forms of environmental pollution. Noise is everywhere.
Research in the U.S. and Europe shows that quiet asphalt reduces highway noise by 3 to 5 dB(a) and more.
Asphalt is the quiet pavement.
Quiet pavement technologies include open-graded surfaces, fine-graded surfaces, and two-layer open-graded pavements. Noise reductions of 3 to 10 decibels are common.