A new report documents a study of the use of the acoustic beamforming technique to measure highway traffic noise levels from large trucks, conducted under the National Cooperative Highway Research Program (NCHRP) Project 08-56. The beamforming technique employs a stationary array of microphones and data acquisition software to measure noise levels from a variety of noise sources on large trucks, including the engine, tires, mufflers, and exhaust pipes. The study validates the beamforming technique as the most appropriate method for mapping and localizing truck noise. The report includes several recommendations based on the research, including updating the current traffic noise models, developing a national database for traffic noise models on different pavement types, and further applying the study results to evaluate pavement and noise barrier designs. For more information, link to NCHRP Report 635, Acoustic Beamforming: Mapping Sources of Truck Noise. (10-21-09)

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A compilation of new technologies, practices, and other tools for environmental field data collection during the analysis of existing conditions, impacts, and potential mitigation required under the National Environmental Policy Act are provided in a new report produced under the National Cooperative Highway Research Program (NCHRP Project 25-25, Task 48). The research sought to develop and maintain an ongoing compendium of environmental fieldwork technologies through an online survey of all state departments of transportation. Detailed follow-up interviews also were conducted with state DOTs that identified themselves as leaders in environmental fieldwork technologies and practices in four disciplines: cultural resources, ecology, water permitting, and noise analysis. Additional surveys of selected consultants of some of the state DOTs were also performed. The report documents results of the surveys for each of the discipline areas and presents conclusions. For more information, link to the Compendium of Environmental Fieldwork Technologies (NCHRP 25-25, Task 48). (10-16-09)

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The Federal Highway Administration has issued a proposed rule to revise its procedures for abatement of highway traffic noise and construction noise. The proposal would clarify definitions, applicability of the regulations under 23 CFR 772, certain analysis requirements, and the use of federal funds for noise abatement measures. The proposal also would include a screening tool and the current state of the practice on addressing highway traffic noise. Highway agencies will be required to submit their revised noise policy to meet the new requirements within six months of publication of the final rule. Comments are due Nov. 16, 2009. For more information, link to the proposed rule. (9-17-09)

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The Federal Highway Administration’s Office of Natural and Human Environment has published a paper listing noise barriers constructed with highway program funds from 1973 through the end of 2007. The listing, which is based on data reported by state departments of transportation, is updated every three years and includes information on length, height, cost, material, location, and year constructed for each state. Trends in noise barrier construction highlighted in the paper including findings that 46 states and Puerto Rico have constructed highway traffic noise barriers, while four states and the District of Columbia have not; state DOTs have spent on average over $100 million in highway program funds per year on noise barriers since the first barriers were constructed in the early 1960s; and most barriers have been made from concrete or masonry block and cost $24 per square foot on average. For more information, link to the Summary of Noise Barriers Constructed by December 31, 2007 and FHWA’s Highway Traffic Noise website. (8-28-09)

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The May-June 2009 issue of the Transportation Research Board’s TR News includes an article on the use of air bubble curtain systems to reduce underwater noise from pile driving at bridge construction projects, which can harm marine species and lead to construction delays. The article, which is part of TRB’s “Research Pays Off” series, explores research conducted by the Fisheries Hydroacoustic Working Group, formed by the California Department of Transportation (Caltrans), FHWA, and the departments of transportation in Oregon and Washington, on the impacts of underwater pile driving noise on fish. For more information, link to Reducing Underwater Sounds with Air Bubble Curtains. (8-3-09)

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The Federal Highway Administration’s National Highway Institute will hold a training seminar on highway traffic noise at Columbia College in Chicago on Aug. 18-20, 2009. The seminar is intended to provide engineers, environmental specialists, designers, and consultants with an overview of issues related to traffic noise and how to reduce impacts caused by highway projects. The seminar will feature topics including basic acoustic principles, determining when a noise analysis is required, and noise mitigation strategies. The seminar also will provide and overview of the FHWA Traffic Noise Model and include a presentation by the Illinois DOT noise specialist on state policies and procedures. For more information, link to the NHI Noise Seminar. (5-21-09)

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