Traffic Noise Attenuation as a Function of Ground and Vegetation (Interim Report)

摘要

The report presents results on traffic noise attenuation by vegetation along highways, and by various ground covers. Noise measurements at various distances were made in regions of three vegetative barrier sites. The sites included: (1) oleander, (2) combination of oleander and redwoods, and (3) pine trees, as part of existing landscaping. Observed noise reductions by the vegetation ranged from 0 to 2.7 dBA, and averaged 0.9 dBA. This was not considered significant from a human perception standpoint. The excess attenuation portion of the project is partially completed. The method of analysis is described and preliminary results indicate that the site parameter, as used in the FHWA Highway Traffic Noise Prediction Model (FHWA-RD-77-108), is much higher than 0.5 used in the model for acoustically absorptive sites.