The noise emitted from vehicles at roundabouts

In Asian cities, many noise-sensitive receivers are located in the vicinity of highways and roundabouts because of the limited supply of usable land and the demand for good transportation. Although roundabouts can carry smooth traffic flow by minimizing the start-stop operations of drivers, the noise emitted from moving vehicles would definitely affect those people who live, work, or study in the vicinity. This article presents an analytical solution of the noise emitted from vehicles at roundabouts by assuming vehicles to be incoherent sources lying continuously on the roundabouts. A simple equation is introduced by which it is possible to relate the noise level at any distance from the center of the roundabout to the noise level measured at the center of the roundabout. (C) 2000 Acoustical Society of America.