Listed below are recent developments pertinent to noise from the past six months. If you would like to suggest a recent development on this topic, please submit a short description to AASHTO (including any pertinent links) on the Share Info with AASHTO form.
The Federal Highway Administration has updated its noise barrier inventory provided by the states for 2014-2016, and provided an associated tool to search the data. The data include state summaries and associated graphs. The search tool makes it easier to access the information, allowing users to filter information based on certain preferences. The FHWA noise regulation requires state highway agencies to maintain an inventory of constructed noise abatement measures that must include aspects such as year of construction, location, features, materials, and unit cost. For more information, link to the tool. (10-6-17)
The Kansas Department of Transportation (KDOT) has issued a report regarding the use of high friction surface (HFS) and multi-layer polymer overlay material to reduce traffic noise levels. KDOT used the statistical pass-by method to measure sound levels along a test strip placed on US Highway 24. The report indicates that the use of HFS does create a quieter sound but it is a smaller decrease in exterior road noise than the goal of a five decibel reduction. For more information link to the report summary. (5-17-18)
The Federal Highway Administration has issued a report concerning the use of solar noise barriers along highway rights-of-way. Such noise barriers would incorporate photovoltaic (PV) systems to reduce noise and produce renewable energy simultaneously. The report provides a review of solar efficiency, safety performance, and economic feasibility of PV noise barriers. Case studies from Australia, the Netherlands, and Switzerland are included to highlight required policies for deployment, barriers to implementation, and maintenance costs. In addition, the report focuses on projects in the U.S., such as the Massachusetts Department of Transportation’s Lexington Solar Retrofit Pilot Program and the state of Georgia’s testing ground, The Ray, set to be the first net zero highway. For more information, link to the report. (August 2017).
The Federal Highway Administration (FHWA) has posted four noise-related resources, including fact sheets on opportunities for use of programmatic agreements and ways to streamline the noise study process. The resources also address several methods for determining and placing nonresidential receptors and case study examples using the single point, frontage-based, lost-sized based and grid-based methodologies. Another fact sheet describes use of sound level descriptors. For more information, link to the resources. (5-31-17)
An updated draft version of the Federal Highway Administration’s traffic noise model (TNM 3.0) has been released for a six-month evaluation and public comment, ending Sept. 14, 2017. TNM 3.0 includes acoustical improvements to support more accurate noise analyses and a new enhanced user interface that incorporates geographic information systems capability. FHWA held a series of webinars in March explaining implementation options for the model. More information, including webinar recordings, requests to download the software, and a form for providing comments, link to the TNM Support Website. (4-20-17)
A map depicting highway and aviation noise at the state and county level has been released by the U.S. Department of Transportation. The map indicates that as of 2014, more than 97 percent of the U.S. population had the potential to be exposed to transportation noise at levels below 50 decibels, roughly the noise level of a humming refrigerator. Less than one tenth of one percent of the population would potentially experience noise levels of 80 decibels or more, equivalent to the noise level of a garbage disposal. The map will be updated annually and eventually account for noise sources from rail and port facilities. The map supplements the National Transportation Atlas Database and is a tool to help prioritize noise-related transportation investments. For more information, link to the map. (3-21-17)
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