Abstract:

This paper demonstrates the use of a geographic information system (GIS) to perform a spatial analysis of traffic noise away from a freeway. The more traditional analysis procedures used by the Federal Highway Administration (FHWA, 1978 and 1982) employ a noise model that is range limited and not designed to handle large-scale topographic variation near a freeway noise source. A digital elevation map of a portion of a freeway in San Diego County that includes a mesa and valley landscape is incorporated into a GIS where a spatial analysis of ray path geometry, substrate, and vegetation is used to evaluate measured noise levels of traffic. Preliminary results indicate that a GIS model of traffic noise provides a more realistic basis for predicting noise impacts, particularly at longer ranges in areas of variable topography.