Highway noise under favorable conditions of generation and propagation.

Abstract

This study describes the long range propagation of highway noise under favorable conditions of generation and propagation.For downward ray bending (temperature inversion and/or downwind propagation) geometrical spreading is principally affected by air absorption. The equivalent absorption coefficient is introduced. Air attenuation of the timeaverage sound level, LAeqT, is calculated for various weather conditions. Finally, for the weather prevailing in the Kyushu District and the percentage of heavy vehicles k=0.5 (typical for night hours), we have found a relationship between LAeqT traffic flow and the perpendicular distance to the highway.