ABSTRACT
This paper examines the impact of meteorological conditions on the propagation of vehicular noise from urban freeways. A parabolic equation model coupled to an analytical Green’s function solution close to the source field is used to compute the refracted sound field up to half a mile from the freeway to predict the noise exposure of residential areas nearby. The model was used in conjunction with meteorological and sound-level measurements taken at two freeway sites over the course of four days in Phoenix, AZ. From the data collected, three test cases of varying levels of atmospheric stratification and wind shear are presented and discussed. The model demonstrates that atmospheric effects are able to raise sound levels by at significant distances away from the highway, causing violations of acceptable limits imposed by the Federal Highway Administration in residential areas that are normally in compliance.
ACKNOWLEDGMENTS
We are extremely grateful to Arizona Department of Transportation (ADOT), Arizona State University (ASU), and University College London (UCL) for their support of this ongoing collaborative research. In particular, we thank Christ Dimitroplos and Fred Garcia at ADOT for their interest and encouragement. The consultants Illingworth-Rodkin assistance in the project in measuring and processing the sound data is also gratefully acknowledged. We also thank Dragan Zajic, Leonard Montenegro, and Adam Christman for their help with the field experiments and subsequent data analysis and the referees for their very constructive and encouraging comments.
