Full-scale model investigations into insertion loss of highway noise barriers under different atmospheric conditions

Abstract

The insertion loss of highway noise barriers can change significantly with atmospheric conditions. The insertion loss of a 14×80-ft tongue and groove wooden barrier constructed at the Pennsylvania Transportation Institute test track near State College, PA was measured under different atmospheric conditions. Point sources consisted of pure tones and random noise. Both sources and receivers were held at fixed distances from the barrier. Wind and temperature profiles were estimated from measurements using similarity theory. Measurements were taken as winds varied in both direction and strength for different temperature profiles. Results from parabolic equation model calculations of the propagation over the barrier are compared to the measured data. A statistical analysis of the changes in the insertion loss measurements is performed. This study demonstrates the effects of atmospheric conditions on the insertion loss of the barrier.