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Petaluma, CA, United States

Donavan P.,Illingworth and Rodkin Inc.
INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | Year: 2014

Vehicle noise measurements were made on an arterial roadway in San Rafael, California before and after a 25 mm overlay of open graded asphalt concrete (OGAC). The purpose of these measurements was to document any reduction in vehicle noise due to the overlay on a 0.8 km section of pavement prior to repaving the entire length of the roadway. The posted speed limit along this test section is 56 km/hr. Of particular concern was the reduction of noise produced by medium and heavy duty trucks accessing a quarry. To quantify the noise reduction, statistical isolated pass-by (SIP) measurements were conducted before and after the overlay along with 10-minute Leq's with traffic counts, and on-board sound intensity measurements (OBSI). The SIP measurements indicated a 9.2 dB reduction for light vehicles averaging 64 km/hr, 5.1 dB for heavy trucks under cruise/deceleration averaging 48 km/hr, and 3.1 dB for heavy trucks under acceleration averaging 42 km/hr. The hourly Leq for all vehicles was reduced by 5.0 dB. The OBSI measurements displayed reductions of 3.5 dB implying that porous nature of the OGAC was significantly influencing the measured wayside noise reduction. Source

Reyff J.A.,Illingworth and Rodkin Inc.
INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | Year: 2015

This paper describes recent experiences permitting marine construction projects that involve pile driving from an acoustical aspect. Marine or aquatic construction projects typically involve the use of heavy construction equipment and pile driving that generates substantial noise. The resulting acoustic impacts to wildlife are a concern to natural resource regulators, particularly those impacts to marine mammals and fish. As a result, biological assessments are prepared that attempt to describe the acoustical impacts to wildlife and identify methods to reduce sound effects. These assessments include the prediction of underwater sound from pile driving that is used to assess impacts to ecological resources. Monitoring plans to ensure that these effects are not greater than predicted are then developed. Finally, monitoring of underwater sound producing activities is conducted and, if necessary, construction activities are modified. © 2015 by ASME. Source

Lodico D.M.,Illingworth and Rodkin Inc.
INTER-NOISE 2015 - 44th International Congress and Exposition on Noise Control Engineering | Year: 2015

A standard method of test for the Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method has been published by the American Association of State Highway and Transportation Officials (AASHTO) under TP-76: 2013. The development of this method was based on research dating back to the early 1980's, with more recent work focusing on understanding the sensitivities of the method to measurement parameters in an effort to reduce the variability of the results. Many of the identified variables, such as equipment selection, vehicle loading, tire selection, and test speed can be controlled by the field crew to result in minimal variability for these tests. Meteorological conditions, however, cannot be controlled in the field and, as a result, a normalization procedure was developed to account for air temperatures and density. This paper summarizes the results of the two primary large-scale research projects that led to the development of this normalization procedure, National Highway Research Programs NCHRP 1-44, and 1-44(1) and applies the developed normalization procedure to the results of a long-term quieter pavement study conducted by the Arizona Department of Transportation. © 2015 by ASME. Source

Donavan P.R.,Illingworth and Rodkin Inc. | Rymer B.,120 N Street
Transportation Research Record | Year: 2011

Between 2003 and 2010, research on the changes in tire-pavement noise generation over time was conducted on 11 textures applied to portland cement concrete. The initial textures included longitudinal tining, burlap drag, and longitudinal broom. Additional texturing was applied to these surfaces in the form of longitudinal grooving of varying depth and spacing and diamond grinding with varying spacer dimensions, as well as a combination of the two. Since their application, these sections have been routinely monitored for tire noise performance with the onboard sound intensity method. As originally measured in June 2003, the range in level between the surfaces was relatively small at 2.7 dB. At 5 years, the range is slightly smaller at 2.3 dB. During the total 71/2 years of the study, the overall noise performance increased at an average rate of about 0.10 dB per year. The study has shown that for different frequency ranges the change in noise level has displayed some variation; the lower-frequency levels have decreased for some pavements with time, while the higher-frequency levels have increased at a rate higher than the overall levels for all pavements. For the higher frequencies, findings suggested that the increased noise was due to polishing of the surfaces. For the lower frequencies, the reduction in noise level was less pronounced with more variability between textures. For the ground surfaces, some evidence was found that indicated that the reduction might be linked to some loss of larger-scale texture as the surfaces were worn down. Source

Donavan P.R.,Illingworth and Rodkin Inc.
Transportation Research Record | Year: 2011

Acoustic measurements were made on several asphalt test pavements at the National Center for Asphalt Technology test track, including five porous pavements. Onboard sound intensity (OBSI) measurements were taken to quantify the tire-pavement noise source strength as a function of pavement parameters. The OBSI results fell into three pavement groupings based on spectral shape. More than other parameters, these groupings were determined by whether the pavement was porous or not and whether it was new or older. The OBSI results also indicated that singlelayer porous pavements were particularly effective at reducing tire-pavement noise source strength at frequencies above 1,250 Hz for designs 18 to 33 mm thick. For a thicker, double-layer porous pavement, source strength reductions extended down to 630 Hz. Porous pavements were also found to be effective in reducing the source strength of the tire-pavement interaction by reducing some tire noise mechanisms and by reducing the sound power level of the source through local sound absorption. Testing was also conducted to evaluate the additional attenuation for sound propagating over porous, sound-absorbing pavements compared with nonporous pavements. From the propagation measurements, all porous pavements produced additional sound attenuation over that produced by the nonporous pavements. The additional attenuation also increased with distance from the source. Source

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