This memorandum updates the Federal Highway Administration’s (FHWA) position on pavement as a noise abatement measure. As part of this update, this memorandum also provides a response to the comments submitted to Federal Register Notice 2013-0014: entitled “Including Specific Pavement Types in Federal-Aid Highway Traffic Noise Analysis”, (Volume 78, Number 89, pages 26847-26848, May 8, 2013). This memorandum supersedes the memorandum entitled “INFORMATION: Highway Traffic Noise - Guidance on Quiet Pavement Pilot Programs and Tire/Pavement Noise Research”, dated January 19, 2005. We also provided update on the Quiet Pavement Pilot Program (QPPP), and other information on quiet pavement research, and tire/pavement noise in noise modeling.
If maintained, effective noise barrier designs continue to provide the same level of noise reduction in perpetuity, despite changes to the surrounding noise environment. The FHWA has applied this policy consistently among all potential Federal-aid highway noise abatement measures, including pavement type and/or texture. Over the past decade, there have been extensive studies on the noise reduction properties of pavement that shows that a pavement type or texture’s ability to provide a noise reduction declines as the pavement ages. As a result, the FHWA had always provided the following guidance through technical assistance when discussing the possibility of pavements as a Federal-aid noise abatement measure:
In addition, 23 CFR 772.9(b), states that “Average pavement type shall be used in the FHWA TNM for future noise level prediction unless a highway agency substantiates the use of a different pavement type for approval by the FHWA.” More detailed discussion on this topic can be found in the FHWA document "Highway Traffic Noise: Analysis and Abatement Guidance", December 2010, page 21.
On May 8, 2013, the FHWA issued Federal Register Notice “Including Specific Pavement Types in Federal-Aid Highway Traffic Noise Analysis” to invite stakeholders and interested parties to provide comments and suggestions on whether and how to include additional pavement types in Federal-aid highway traffic noise analyses. As a guide, the FHWA listed seven questions to solicit information from the public. Sixteen state highway agencies and three interested parties ended up commenting on. Two of these questions were:
The FHWA’s review of the comments received generally showed that:
Based on feedback from the Federal Register Notice, the FHWA will continue to evaluate the existing data that makes up the FHWA Traffic Noise Model’s (FHWA TNM) Reference Energy Mean Emission Levels (REMELs) and consider ways to integrate new data, if appropriate, to increase the accuracy of highway noise prediction. Noise generated at the tire/pavement interface contributes to the overall highway traffic noise levels that sensitive noise receptors are exposed to along roadways. The inclusion of additional specific pavement types in noise modeling can reduce the under- or over-predictions that can occur from using a national average.
In 2003 the Arizona Department of Transportation (ADOT) and the FHWA entered into the Quiet Pavement Pilot Program (QPPP). The intent of the ADOT QPPP was to evaluate ADOT’s asphalt rubber-asphalt cement friction course (AR-ACFC), over a 10 year time period, for its effectiveness as a quiet pavement strategy, and changes to its noise reduction properties. ADOT chose to use a 4 dB reduction from the ARFC. ADOT will continue to monitor some segments where the pavement life cycle is exceeding 10 years and use that data as a basis to submit to FHWA for consideration of a minimum life cycle dB benefit. This life cycle may be somewhere in the range of 12 to 15 years.
Since 2003, no other highway agency has requested to initiate a QPPP. Any new QPPPs would be required to evaluate the pavement for its full life cycle to avoid premature overlay of the pavement solely to restore the noise reduction.
Several highway agencies have developed their own quieter pavement research programs and identified which, of their already approved pavements, are the quietest. Some highway agencies construct quieter pavements on their highways when appropriate, but not as noise abatement measure as outlined in 23 CFR 772. Although not a noise abatement measure as defined by the FHWA noise regulation, the FHWA encourages highway agencies to research their quieter pavements and construct these pavements when appropriate.
In summary, 23 CFR 772 does not allow for the use of pavement type or surface texture as a noise abatement measure. Based on the comments provided to the Federal Register Notice, the FHWA will continue to consider pavements as contributing to the noise abatement measure if evaluated for the pavement’s full life cycle. The FHWA will allow new QPPPs, per the new conditions discussed above, and encourages highway agencies to continue researching their pavement type(s) and surface texture(s) and construct those pavements in accordance with their agency’s requirements. The FHWA will continue to investigate updates to the REMEL and “average pavement type” for noise analyses on projects subject to the requirements of 23 CFR 772.