A much smaller segment of the U.S. resident population has the potential to be exposed to higher levels of aviation and Interstate highway noise. Less than one-tenth of a percent of the population could potentially experience noise levels of 80 decibels or more, equivalent to the noise level of a garbage disposal (See Table).

The purpose of the noise map is to facilitate the tracking of trends in transportation-related noise, by mode, and collectively for multiple transportation modes. The data allow viewing the national picture of potential exposure to aviation and highway noise. The data also allow viewing of the potential exposure at the state or county level.

The National Transportation Noise Map will be an addition to the National Transportation Atlas Database (NTAD), a set of nationwide geographic databases of transportation facilities, networks, and associated infrastructure available from the BTS Geospatial Data Catalog. The layers will be updated on an annual basis, and future versions of the National Transportation Noise Map are envisioned to include additional transportation noise sources, such as rail and maritime.

The BTS map contains aircraft and road noise inventory data provided as web map services (WMS) for use with Geographic Information Systems (GIS), computer programs that can store, analyze, and present spatial or geographic data.

The geospatial data provides a basis for understanding what-if scenarios and helping policy makers to prioritize noise-related transportation investments. Using the National Transportation Noise Map data, BTS highlighted the percentage of total U.S. resident population that had the potential to be exposed to the following A-weighted 24-hour equivalent sound levels (LAEQ) (a-weighted, average sound level for the day) from aviation and Interstate road noise in the year 2014.