Petaluma, CA, United States
Petaluma, CA, United States

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Donavan P.,Illingworth and Rodkin Inc. | Lodico D.,Lodico Acoustics LLC
Transportation Research Record | Year: 2013

A highway-widening project was completed on US-101 near San Rafael in Northern California with the addition of a high-occupancy vehicle lane in each direction, relocation of the southbound existing sound wall, and the addition of a multipurpose path. Because there was an existing sound wall in the northbound direction, additional conventional noise abatement was not considered feasible under California Department of Transportation and FHWA policies for this Type 1 project. However, two elements were included to improve aspects of existing noise environment. The elements included overlaying all lanes of the completed project area with quieter, open-graded asphalt and applying absorptive treatments to the traffic side of both barriers. To document the potential benefit of these features, the Transit Authority of Marin commissioned a study of preproject and postproject noise levels. Included were measurements of wayside noise levels above and behind the northbound sound wall and of tire-pavement noise using the onboard sound intensity method. Measurements indicated that 6- to 7-dB reductions in wayside noise levels both above and behind the barrier could be accounted for by reduction in tire-pavement noise. Effectiveness of added absorption could not be directly isolated in the measurements, so the benefit of this feature was assessed through acoustic modeling. Results indicated that additional reductions of 3 to 5 dB could occur for receptors elevated above the roadway, shielded from ongoing traffic but with a view of the opposing sound wall, and at distances of 500 ft or more. Near the highway, reduction provided by absorptive treatment was 1 to 1 1/2 dB or less.


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.


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.


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.


Donavan P.R.,Illingworth and Rodkin Inc.
24th National Conference on Noise Control Engineering 2010, Noise-Con 10, Held Jointly with the 159th Meeting of the Acoustical Society of America | Year: 2010

When quieter pavements are used for purposes of reducing traffic noise levels, one issue of concern is how long will the noise reduction performance be maintained, or, what is its "acoustic longevity". To address this issue, both the California Department of Transportation (Caltrans) and the Arizona Department of Transportation (ADOT) established on-going research projects on a number of different pavement types including the broad groups of asphalt and portland cement concrete (AC and PCC, respectively). These pavements have been monitored routinely with on-board sound intensity (OBSI) measurements since the time of initial construction or, in some cases, since the time when the OBSI method was implemented for pavement evaluation in 2002. This yielded data over periods of 4 to 7 years. The results of these measurements are presented and discussed. In another approach of evaluating acoustic longevity, pavements of the same construction, but different years of build have also been evaluated to examine longer periods of time. The results of this approach are also presented along with a discussion of the issues involved with the two methods.


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.


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.


Donavan P.R.,Illingworth and Rodkin Inc.
SAE International Journal of Passenger Cars - Mechanical Systems | Year: 2011

With increasing use of the constant speed pass-by conditions to capture the noise generated by this portion of the vehicle operating cycle, knowledge of the contributing sources of noise was become increasingly important. For frequencies above 400 Hz, the noise is dominated by tire/pavement noise as can be demonstrated by comparing on-board sound intensity (OBSI) measurements to constant speed pass-by noise levels. At lower frequencies, direct on-board measurements become more difficult as the tire/pavement noise source strength decreases with decreasing frequency and microphone induced wind noise increases. To investigate the contribution of sources at these lower frequencies, cruise and coast pass-by measurements were made for a number of different pavement types and two different tire designs at test speeds of 56, 72, and 97 km/h over a frequency range from 50 to 10,000 Hz. OBSI measurements were also conducted for these same conditions. From the pass-by measurements, powertrain noise was separated from "rolling" noise by comparing cruise and coast operation. For coast conditions, the noise levels below 400 Hz were found not to depend on pavement type and texture or on tire design unlike the higher frequencies. Further, the speed dependencies of the levels below 400 Hz were more consistent with aerodynamic noise than with those of the tire/pavement noise. Contribution of aerodynamic noise was also indicated with wind tunnel measurements of vehicle exterior noise. Using these results, the relationship between the various noise sources at these lower frequencies was investigated. © 2011 SAE International.


Donavan P.R.,Illingworth and Rodkin Inc.
Transportation Research Record | Year: 2014

In 2011, pavement on an eight-lane portion of U.S. Highway 101 in San Rafael and Novato, California, was rehabilitated with the application of an open-graded asphalt concrete (OGAC) overlay as part of a larger project to improve the traffic flow along the 101 corridor. Residents in the area of rehabilitation had periodically complained to the local transportation agency about traffic noise. For an understanding of the noise reduction expected after the application of the new OGAC, wayside traffic noise levels and onboard sound intensity (OBSI) levels were measured at two sites: the site where the new pavement was to be placed and a nearby site that had received new OGAC 1 year earlier. The results indicated that a reduction of 7.8 dB in OBSI tire-pavement noise should be expected, along with a reduction of 7.8 to 8.4 dB in wayside traffic noise. The measurements were repeated after the OGAC application; OBSI reductions of 7.1 dB were found, and reductions of 10.5 and 11.2 dB were found for the wayside levels measured 60 ft from the highway. The comparison of results from previous studies of sound propagation over porous pavements led to the conclusion that this additional reduction in the wayside levels of 3.4 and 4.1 dB compared with the tire-pavement source levels was attributable to the sound absorption provided by the porous pavement.


Donavan P.R.,Illingworth and Rodkin Inc.
SAE International Journal of Passenger Cars - Mechanical Systems | Year: 2012

The results of a series of tests were performed that are used to investigate the contribution of aerodynamic noise to lower frequency passenger car interior and exterior cruise noise levels. Wind tunnel measurements were used to isolate aerodynamic noise from tire-pavement and engine noise and to indicate that the vehicle underbody is a significant source region for both interior and exterior noise. Comparing interior on-road measurements to the wind tunnel results, it was found that aerodynamic noise was slightly less than an equal contributor to cruise noise averaging 4.8 dB lower than the road levels between 50 and 400 Hz at a speed of 80 km/h. At 140 km/h, the difference dropped to 2.3 dB indicating that the aerodynamic noise was the major contributor. For exterior pass-by, aerodynamic noise levels were found to account for almost all of the noise measured during coast-by conditions in the frequency range from 50 to 400 Hz at 97 km/h. This finding was substantiated by additional pass-by testing using different tires on a variety of pavements. It was further found that aerodynamic noise was likely a partial contributor to pass-by noise levels at vehicle speeds as low 56 km/h. These influences were also indicted by comparing tire-pavement source levels measured on-board to the overall cruise and coast pass-by levels. Although the influence of aerodynamic noise will vary with tire design, vehicle design, pavement, and vehicle speed, this paper should provide motivation for considering it in both predicting and reducing interior and exterior noise. © 2012 SAE International.

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