Traffic noise has actually ended up being more of a problem in some neighborhoods because there are more automobiles on the road, and heavier automobiles entirely, in addition to cars driving at greater speeds.
The noise stems in part from car engines, wind and other elements, but when automobiles drive at speeds of 60 miles per hour or higher, roadway sound results primarily from contact between the tires and the road, according to Dr. Donavan.
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For residents who live near busy highways, the sound is disturbing and may be hazardous to their health. It also lowers home values and requires costly noise barriers. Engineers state newer pavements could lower noise by three to 5 decibels, an audible difference.
Roads normally are paved with concrete, a rigid surface made of stone and sand and bound with cement. Or they are paved with asphalt concrete, a more versatile surface area where the binder of the stone and sand is asphalt, the sticky compound left after oil has actually been improved.
The noise level of a roadway depends on 3 factors: the appearance of the roadway surface area; its stiffness; and its porosity– how huge the air holes are. Too smooth a surface isn’t really excellent since it can cause squeaking, however too bumpy a surface causes rumbling.
One trick for quieting pavement is to offer it a “unfavorable” structure, or small divots and gouges, according to Robert Rasmussen, a pavement engineer at Transtec Group Inc., a pavement-engineering and design company.
However if those divots get blocked, the sound reduction is removed. In Europe, where the European Union has mandated that metropolitan areas utilize quieter pavement, a giant vacuum-cleaner-like device is used to suck the grit from the roadway divots, according to researchers.