Case Study:

Waterloo, Iowa

Methodology

Determine Available Data

An emissions dispersion model such as CAL3QHC requires the following information:

• Location of each roadway link (starting and ending X-Y coordinates);
• Traffic volumes and speeds by link;
• Composite running emission factors by link, which are obtained from MOBILE based on average speed and percent of traffic by vehicle type;
• Various information on intersections, such as coordinates, signal cycle length, red time, and saturation flow rate;
• Composite idle emission factors from MOBILE; and
• Meteorological data, including typical wind speeds and directions and other parameters.

Noise models require similar data on traffic volumes, speeds, and mix of vehicles by link. Optional data to refine noise estimates include the height of adjacent structures, elevation of surrounding terrain, and traffic mix, speed, and volume of intersecting streets.

Forecast traffic data should be obtained with and without the proposed project. The regional MPO may have traffic volume and speed data for major facilities. Data may also be available from traffic modeling for the proposed project.

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