Case Study:

Waterloo, Iowa

Methodology

Estimate Noise Impacts

Noise contours can be estimated, similar to the air pollution contours developed above. A noise model such as FHWA's Traffic Noise Model (known as STAMINA in its previous version), can be used to determine noise levels as a function of traffic volume, mix, and speeds. In the Waterloo case study, the authors use MINNOISE, an updated version of STAMINA developed by the Minnesota Department of Transportation. While additional data such as height of adjacent barriers or local topography can be used to refine noise estimates, a simplified set of inputs based only on traffic were utilized in this analysis.

Noise models typically estimate noise levels as a function of distance from the roadway centerline. Contours can be plotted in GIS by creating a new shapefile and drawing buffers around a roadway link. Noise levels are then associated with each buffer based on the distance of the buffer from the link. To model roadways with intersections, the road may need to be broken into multiple segments, for which vehicles are designated as accelerating, decelerating, or cruising.

Figure 3. Noise Contour Overlaid on Minority Population

Source: Forkenbrock and Schweitzer (1997).

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