Vertical Propagation Regularity of Road Traffic Noise

The vertical propagation regularity,i.e.noise level going up first and then down with height,is verified through measurements of the noise level outside the window on site of six street buildings.For reasoning of the regulariy,analysis of measured data,theoretical computation and application of noise prediction software Cadna/A were combined.It is shown that the vertical propagation regularity of road traffic noise correlates with the features of road itself.The noise level increases under certain height,but beyond that height the noise level will attenuate according to line source theory.