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One of the few bright spots in the U.S. is somnolent Memphis, which has won 14 "Quietest City" awards from the National Noise Abatement Council for a strict program that requires thrice-yearly inspection of car brakes and mufflers, permits horn honking only in emergencies, and prescribes fines for people who keep noisy pets. But more needs to be done, says Physicist Knudsen: "The reduction of noise results in increases in output of labor and in human well-being that usually more than justify the cost of reducing the noise."
* The unit for measuring relative loudness of sounds, the decibel is approximately the smallest degree of difference that, a human ear can detect between the loudness of two sounds.