A comprehensive model for the straight-edge noise barrier: Theory and experiment

A mathematical model has been developed which describes the acoustic diffraction from a point source to a point receiver over a straight edge located on an impedance-covered ground plane. Appropriate frequency summations and integrations over an incoherent line of point sources yield values of excess attenuation that may be expected from real-world highway noise barriers with car or truck traffic flow. The model accounts for such factors as the ground reflections (“ground effects”) on both sides of the barrier, arbitrary impedance cover on each face of the barrier, “tilt angles” for the barrier itself, transmission loss through the barrier, as well as the double-diffraction effect due to a ground-plane impedance discontinuity on the source side of the barrier. This paper addresses the rigid perpendicular barrier on various ground surfaces and compares the predictions to 15-scale model experimental results. [Work supported by FHWA.]