A Multi-Modal National Transportation Noise Map
In a world that offers the flexibility to choose to travel by car, bus, plane, train, or boat, the noise that is generated by these transportation modes must be managed. While each mode is regulated separately, people are not exposed to noise from these modes separately. Recognizing the need to assess noise from different transportation sources together, in March 2017 the Bureau of Transportation Statistics (BTS) and the Volpe Center developed the first national, multi-modal, transportation-focused noise dataset with the purpose of facilitating the tracking of trends in noise levels over time.
Phase 1
In the first phase of the National Transportation Noise Map project, a simplified noise modeling process was created to model aviation and road noise for the nation for 2014. This process included the use of the Federal Aviation Administration’s (FAA) Aviation Environmental Design Tool (AEDT) for aviation noise modeling, and algorithms from the Federal Highway Administration’s (FHWA) Traffic Noise Model (TNM) for road noise modeling. Given the large scale of this modeling effort, simplifications were made and assumptions are described in supporting documentation.
Noise levels were modeled using the 24-hour, A-weighted equivalent sound level (LAeq,24) noise metric and down to 35 dB(A) LAeq,24.
The National Transportation Noise Map dataset has undergone limited subject matter expert verification and validation (V&V). Additional V&V may be considered with future datasets.
The 2014 aviation and road noise data are available to the public as part of the National Transportation Atlas Database (NTAD) from the BTS Geospatial Data Catalog. BTS has also provided an online web-viewer here.
Considerations
To make the most of this unique data set, the following should be considered.
The intended purpose of this dataset is to facilitate the tracking of trends in transportation noise for the nation over time and to provide the ability for policy makers and the public to view transportation noise in a multi-modal context. Due to the simplified noise modeling assumptions, the dataset should not be used to evaluate noise levels at individual locations for a given year. However, this dataset is well suited to assist in identifying areas that might benefit from more detailed analyses.
When viewing these results, it is important to remember that only aviation and road noise are included. Other ambient noises, including other transportation modes or non-transportation sources, are not included. For example, the correct interpretation for areas that are in the 35 dBA or lower range is that in 2014, the 24-hour average noise level due to aviation and road noise sources was approximated to be 35 dBA or lower.
The LAeq,24 metric used for this analysis is not the same as is commonly used in more in-depth analyses; comparisons between this dataset and more detailed, site-specific analyses are not necessarily appropriate.
Media Coverage and the Future
There has been intense media interest in the National Transportation Noise Map from the time it was released. The result has been extensive media coverage on the release of these data from the Washington Post to the Atlanta Journal Constitution to many local outlets. The official press release from BTS can be found here.
BTS and Volpe intend to provide datasets for additional years and hope to add additional transportation noise sources in the future.
