Development of Traffic Noise Screening Tool

There are many instances where noise studies were completed for projects that were not likely to result in noise impacts. State Highway Agency can pursue a programmatic agreement (PA) with FHWA to try to reduce the number of unnecessary noise studies. The analysis conducted in support of the PA included a wide range of Average Daily Traffic volumes between 500 and 14,000. The parameters of the PA rely solely on calculated noise levels at specified traffic volume, mix, speed, and roadway designs. Gannett Fleming performed the analysis using the FHWA TNM 2.5 to develop a series of TNM cases to test impact thresholds at various speed and slope conditions. Using the data above, GF developed a regression model that will enable SHAs to expand the programmatic agreement and provide answer for a finer grid of traffic volume. Gannett Fleming proposed a two-tier approach. Tier 1 used statistical analysis to determine how the various parameters are co-dependents and which parameter is the dominant variable. Tier 2 focused on building a regression model that includes all these variables. Using the regression model results, GF developed a Graphical User Interface that provided a tool for engineers to use the noise programmatic tool.