most forecasts, the U.S. population is projected to grow by over 100 million by
2050. As demand for transportation increases, transportation-related noise will
also change. The Bureau of Transportation Statistics (BTS) has started a
national, multi-modal transportation noise mapping initiative to facilitate the
tracking of trends in transportation-related noise as changes occur at an
multi-modal, National Transportation Noise Map is intended to facilitate the
tracking of trends in transportation-related noise by mode and collectively.
These maps include simplified noise modeling that cannot be used to evaluate noise levels in individual locations or at specific times and should not be used for regulatory purposes.
national transportation noise map is developed using a 24-hr equivalent A-weighted
sound level (denoted by 24-hr LAeq) noise metric. The results represent
the approximate average noise energy due to transportation noise sources over a
24-hour period at the receptor locations where noise is computed, expressed in decibels. To learn more about what a decibel is, what an A-weighted sound level means, and the LAeq noise metric, please visit: "What's a Decibel (dB)?"
Population Potentially Exposed to Noise
percent of the total U.S. population potentially exposed to aviation and road
noise, as defined by a 24-hour average sound level, increased from 2016 to
2018. Most US states (37 states) experienced an increase in the number of people
affected by aviation noise between 2016 and 2018, while 13 states and the
District of Columbia saw a decrease. The distribution of states experiencing
changes in road noise was similar, with 31 states and the District of
Columbia seeing an increase and 19 states experiencing a decrease between 2016
Population potentially exposed to aviation noise, 2016 and 2018
Population potentially exposed to road noise, 2016 and 2018
Population potentially exposed to combined aviation and road noise, 2016 and 2018
Population potentially exposed to passenger rail noise, 2018
(in the contiguous United States)
Population potentially exposed to combined aviation, road and passenger rail noise, 2018
(in the contiguous United States)
some regions, there was an observed decrease in the percent of the population
potentially exposed to aviation noise
Vermont experienced the greatest percent decrease of 33%: 10%
of the population was potentially exposed to aviation noise in 2016 compared to 7% in 2018. New Mexico and South Dakota had the second and third largest
percent decreases of 33% and 27% respectively. One factor that may contribute
to the decreases in potential exposure to aviation noise may be the decrease in
military operations at joint military/commercial airports in these states in
2018 compared to 2016. In Vermont, for example, the number of military
take-offs and landings at these airports decreased from about 4,600 in 2016 to
about 2,700 in 2018. Since air traffic and aircraft type are major factors in
the calculation of aviation noise, fewer flights with military aircraft could
lead to an overall lower potential exposure to aviation noise.
For certain states, there was also an observed decrease in the percent of the population potentially exposed to road noise.
Georgia experienced the greatest percent decrease of 33%: 14% of the population was potentially exposed to road noise in 2016 compared to 9% in 2018. Minnesota and Vermont had the second and third largest percent decreases of 21% and 7% respectively. One factor that may contribute to the decreases in potential exposure to road noise may be the decrease in average daily traffic on certain urban highways in these states in 2018 compared to 2016. In Georgia, for example, the weighted average daily traffic per lane on all urban principal arterials decreased from 7,771 vehicles in 2016 to 7,677 vehicles in 2018. Since daily traffic is a major factor in the calculation of road noise, lower traffic volumes could lead to a lower potential exposure to road noise.
U.S. Department of Transportation, Bureau of Transportation Statistics, 2020 (Washington, DC: 2020).
Aviation noise: Flight
are averaged into a single average annual day. Airports with an average of 1 or
more jet departures per day are included in the analysis (note: airports with exclusively
military operations were excluded; however, military operations at joint-use or
commercial airports were included). Helicopter operations are not included in this effort. For the year 2016, this resulted in the modeling of operations at 685 airports. In the year 2018 this resulted in modeling operations at 747 airports.
Road noise: Average Annual Daily Traffic (AADT) values are used in
conjunction with vehicle types and speed to compute road noise using TNM’s
acoustical algorithms. AADTs are obtained from FHWA’s Highway Performance
Monitoring System (HPMS), which also describes the road types
included in the National Transportation Noise Map.
Rail noise: General Transit Feed Specification (GTFS) data are used in conjunction with the
North American Rail Network (NARN), and FRA’s Highway-Rail Crossing Inventory
to obtain operational data, route information and locations of grade crossings,
and quiet zones. The GTFS data provides
information on the representative daily traffic and is obtained by counting the
number of trips that each train line makes on a representative weekday in the
fall. The traffic count is used in conjunction with train speed to compute the
overall rail noise produced by each transit system.
aircraft flight operation data are derived from the schedule data in the
Traffic Flow Management System (TFMS), while 2018 aircraft flight operation
data are derived from the MITRE threaded track process. Air traffic counts from
the Air Traffic Activity Data System (ATADS) are also considered for both 2016
and 2018. By combining data from the Air Traffic Control System Command Center
(ATCSCC), the Air Route Traffic Control Centers (ARTCCs), and major Terminal
Radar Approach Control (TRACON) facilities, TFMS, the MITRE threaded track process,
and air traffic counts from the Air Traffic Activity System (ATADS) enable an
accurate representation of all Instrument Flight Rules (IFR), Visual Flight
Rules (VFR), and local flights in US airspace (note: helicopter operations are
not included in this effort). Departure and arrival procedures are determined
from detailed radar track data in the terminal area. For 2018, this radar data came directly from
the MITRE threaded track process; 2016 leveraged the Performance Data Analysis
and Reporting System (PDARS).
 Grade crossings and tunnel locations may be incomplete for Amtrak routes. Grade crossings and tunnel locations that are shared with commuter lines or that are near major metropolitan areas are included.