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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>Propeller cavitation on small craft: Underwater noise measurements and visualisation from full-scale trials</title>
      <link>https://trid.trb.org/View/2476666</link>
      <description><![CDATA[Propeller cavitation is a significant contributor to vessel underwater radiated noise (URN). It is often assumed to be the major contributor for large vessels at higher speeds, but very little work is available in the literature on the role of cavitation on small boat propellers. In this work, data from two trials are presented to show how cavitation develops on small boats and how this contributes to the overall sound levels. Camera footage is combined with hydrophone measurements to determine the cavitation inception speed and this shows that tip vortex cavitation can appear at 5 knots. The emergence of cavitation is accompanied by a sharp rise in the URN levels. Cavitation due to gas bubbles being pulled close to the propeller blades is observed at speeds as low as 4 knots, leading to either bubble collapse close to the blades or the tip vortex cavitating downstream of the propeller. Wavelet analysis is used to investigate the makeup of the high frequency noise, providing insights into the types of cavitation that are present and how they scale with speed. This shows that high frequency noise from cloud cavitation increases far more substantially with speed than for tip vortex cavitation.]]></description>
      <pubDate>Wed, 18 Dec 2024 15:57:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2476666</guid>
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    <item>
      <title>Aspects of the measurement of the acoustic transfer function in a cavitation tunnel</title>
      <link>https://trid.trb.org/View/1600984</link>
      <description><![CDATA[Model scale experiments represent one of the most effective, and probably the most commonly used, approaches for the study of cavitating propeller noise. Despite this, the acquirement of consistent data of propeller noise from tests in model scale facilities is still a challenging task. Data collected with such an approach are usually affected by several scale effects and facility related issues which make such experiments still very complex. Among others, the effect of the facility itself as acoustical surrounding must be carefully addressed in order to properly estimate propeller source levels in ideal free field conditions. This is currently carried out, when possible, by measuring facility transfer functions and applying such functions as a correction to measured noise spectra. The development of robust procedures for the measurement of these transfer functions is thus very important. In the present work, this problem is addressed by discussing in details techniques, merits and possible problems related to this topic.]]></description>
      <pubDate>Thu, 27 Jun 2019 14:00:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1600984</guid>
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    <item>
      <title>HAARP Diesel Engine-Generator Noise Study: Phase 2 Addendum to January 4, 2005 Letter Report</title>
      <link>https://trid.trb.org/View/1592087</link>
      <description><![CDATA[This document is an addendum to the January 2005 letter report “HAARP Diesel Engine-Generator(s) Noise Study”, which presented the results and corresponding analysis of an outdoor noise measurement program conducted by the John A. Volpe National Transportation Systems Center’s Acoustic Facility (Volpe Center) at the United States Air Force’s High Frequency Active Auroral Research Program antenna array (HAARP) in Gakona, AK from September 27th through 30th, 2004. This memorandum is broken up into six sections. Section 1 provides an introduction. In Section 2 the overall purpose of the noise study is presented. In Section 3 the results and the compliance criteria for the applicable standards and regulations from the January 2005 letter report are summarized. Next, in Section 4, the measurement methodology used to collect the HAARP noise data is presented, including short descriptions of the measurement site, microphone locations, measurement equipment, and the data collection procedure utilized during the measurement program. In Section 5, a brief overview of the data processing effort is presented, consisting of acoustic data processing procedures, verification of data quality, and the calculation of the noise metrics. The noise data are then analyzed for compliance with the applicable standards and regulations. The final section, Section 6, of this memorandum consists of a presentation of results, conclusions and recommendations.]]></description>
      <pubDate>Sun, 24 Mar 2019 20:11:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1592087</guid>
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    <item>
      <title>Comprehensive Evaluation of Asphalt Pavement Acoustic Performance by Using Onboard Sound Intensity Method</title>
      <link>https://trid.trb.org/View/1496397</link>
      <description><![CDATA[Noise pollution due to highway traffic is a dominant source of environmental pollution and has drawn the attention of transportation agencies worldwide. Noise barrier walls are often used to mitigate traffic noise. These barrier walls are expensive and not efficient in some cases. Therefore, there is a pressing and growing need to design roads that have a low noise level. To identify and construct quieter pavements, it is necessary to measure the tire-pavement noise levels at the source. An accurate noise measurement at source allows engineers to quickly measure and compare pavement acoustics in great detail. Therefore, a reliable standard noise measuring method should be identified and maintained so that the data can be compared nationally and internationally. This paper presents the evaluation of acoustic performance of asphalt pavements in the State of Qatar. The researchers established a test setup for measuring the noise at source using the on board sound intensity (OBSI) method and examined the on-road applicability of the system as well as repeatability and reproducibility of acquired data. The test results demonstrated that the established OBSI setup is capable of measuring the sound intensity with excellent repeatability and reproducibility. In addition, the results showed that the tire-pavement noise is significantly affected by pavement age, vehicle speed, and tire type. The pavements in Qatar were found to have relatively higher noise level compared to typical dense graded asphalt pavements in Europe and US. The findings of this study demonstrate the need to consider alternative asphalt mixture design in Qatar.]]></description>
      <pubDate>Wed, 28 Feb 2018 13:25:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1496397</guid>
    </item>
    <item>
      <title>Challenges for Tire Noise Evaluation on Common Pavements</title>
      <link>https://trid.trb.org/View/1431898</link>
      <description><![CDATA[Developing common methods of noise evaluation and facilities can present a number of challenges in the area of tire/pavement noise. Some of the issues involved include the design and construction of pavements globally, the change in pavement over time, and variation in the noise produced with standard test tires used as references. To help understand and address these issues for airborne tire/pavement noise, acoustic intensity measurement methods based on the On-board Sound Intensity (OBSI) technique have been used. Initial evaluations have included measurements conducted at several different proving grounds. Also included were measurements taken on a 3m diameter tire noise dynamometer with surfaces replicating test track pavements. Variation between facilities appears to be a function of both design/construction and pavement age. Consistent with trends in the literature, for smooth asphalt surfaces, the newest surface produced levels lower than older surfaces. For more aggressive, exposed aggregate concrete surfaces, the levels produced appear to depend more on the roughness built into the surface rather than aging effects. The tire noise dynamometer produced overall levels slightly higher than the actual pavements especially at higher frequencies. The long term stability and durability of the dynamometer surface make it a useful reference for evaluating the actual pavements over time.       ]]></description>
      <pubDate>Mon, 22 Jan 2018 10:48:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1431898</guid>
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    <item>
      <title>Truck Noise Levels on Upgrades and a Simple Method for Noise Prediction</title>
      <link>https://trid.trb.org/View/1493371</link>
      <description><![CDATA[A simple method for predicting the noise due to heavy trucks on interstate upgrades was developed from mathematical modelling, and the findings of passby and onboard measurements. This method provides speed and noise emission level inputs to the STAMINA 2.0 traffic noise computer program. It predicted the noise from heavy trucks on interstate upgrades more accurately than STAMINA 2.0 alone (1.75 dBA more accurately on average). Truck passby noise measurements were made on a 2 mile long, 4% interstate highway upgrade at one location just before the upgrade and at three locations on the upgrade. Truck noise measurements were also made on upgrades and ramps with a microphone on board a test truck. Heavy truck noise levels measured near the top of the 4% upgrade were more than a decibel (dBA) lower than on the preceding level roadway. Also, speeds measured on the upgrade were considerably higher than those given in the 1985 Highway Capacity Manual. The onboard noise measurements on upgrade roadways corroborated the passby measurement results. Onboard measurements on ramps indicated that the medium truck's noise level was always less on the various types of ramps than it was on the mainline roadways they adjoined.]]></description>
      <pubDate>Mon, 08 Jan 2018 17:22:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1493371</guid>
    </item>
    <item>
      <title>On-board Measurement Techniques to Quantify Underwater Radiated Noise Level</title>
      <link>https://trid.trb.org/View/1445944</link>
      <description><![CDATA[Cavitating ship propellers are known to be the dominant noise source contributing significantly to the underwater radiated noise (URN) level. Innovative measurement methods using on-board devices need to be further investigated as they offer a serious alternative to traditional methods in terms of cost-efficiency and practicality. This exploratory study combined simultaneous on- and off-board noise and vibration measurements with cavitation views captured by digital photography and high speed cameras.Comprehensive full-scale trials were conducted on Newcastle University’s research vessel, The Princess Royal, in the framework of the FP7-EU project SONIC. On-board data were captured from multiple measurement systems (including hull pressure sensors, accelerometers, optical devices, shaft strain gauges) provided by SONIC project partners CETENA, Wärtsilä, University of Southampton and Newcastle University. A new semi-empirical correlation method based on cavitating propeller pressure fluctuation and the URN level was established. Results offer clear evidence of successfully estimating URN with on-board measurements up to the middle frequency region where the blade passing fundamental and low harmonic frequencies occur. These illuminating insights reported in this paper provide valuable benchmark sea trial data in full scale.]]></description>
      <pubDate>Mon, 27 Feb 2017 17:12:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1445944</guid>
    </item>
    <item>
      <title>Understanding the Fundamentals of Boxer Engine Behavior on Sound Quality</title>
      <link>https://trid.trb.org/View/1434636</link>
      <description><![CDATA[An engine configuration has a significant influence on the sound quality from the powertrain. Whilst the fundamental order content can be readily apparent from the firing order over the engine, or bank of a V engine, some characteristics and how the engine design can influence them requires some more specific investigation. Understanding, on a fundamental level, the aspects of the engine design which influence these characteristics is critical to allow more detailed analysis and development work to be focused appropriately.         The configuration of a Boxer engine gives a distinctive sound characteristic producing a unique sound compared to an In-Line configuration. Depending on the application it may be desirable to enhance or subdue some of these characteristics. The fundamental differences affecting the sound characteristics of a 4 cylinder Boxer engine in comparison to an In-Line engine are investigated by consideration of component loading and structural deformations across different excitation orders. Specifically fundamental comparisons are made on engine structural deformation, cranktrain-block interaction, piston loading and valvetrain loading.         The process described in this paper can be applied to determine which critical aspects of the engine design should be a focus for helping to develop the desired sound characteristic. Finally it is discussed how this process can be applied to other configurations for the same purpose.       ]]></description>
      <pubDate>Thu, 05 Jan 2017 16:22:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1434636</guid>
    </item>
    <item>
      <title>Human Response to Aviation Noise: Development of Dose-Response Relationships for Backcountry Visitors - Volume I: Study Methods</title>
      <link>https://trid.trb.org/View/1440558</link>
      <description><![CDATA[The Federal Aviation Administration and National Park Service conducted joint research to better understand the effects of noise due to commercial air tour operations over units of the National Park System. To evaluate the relationship between aircraft noise exposure and the quality of National Park visitor experience, research was conducted at backcountry sites providing day- and overnight-hiking and camping opportunities. This research expands upon work performed during the 1990’s at frontcountry sites. Over 4600 visitor surveys and fifty days of acoustical measurements were collected and analyzed to develop dose-response relationships for backcountry visitors. This report, the first of two volumes, describes the study methods, visitor surveys, research locations and data collected. Volume two describes the model-fitting approach used to identify the noise exposure metrics and mediator variables that best predict visitor responses to aircraft noise. The models developed can be used as a tool to evaluate potential effects of air tours on visitors to National Parks.]]></description>
      <pubDate>Thu, 29 Dec 2016 17:03:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/1440558</guid>
    </item>
    <item>
      <title>Human Response to Aviation Noise: Development of Dose-Response Relationships for Backcountry Visitors - Volume II: Results and Analyses</title>
      <link>https://trid.trb.org/View/1440556</link>
      <description><![CDATA[The Federal Aviation Administration and National Park Service conducted joint research to better understand the effects of noise due to commercial air tour operations over units of the National Park System. To evaluate the relationship between aircraft noise exposure and the quality of National Park visitor experience, research was conducted at backcountry sites providing day- and overnight-hiking and camping opportunities. Over 4600 visitor surveys and fifty days of acoustical measurements were collected and analyzed to develop dose-response relationships for backcountry visitors. This report, the second of two volumes, describes the model-fitting approach used to identify the noise exposure metrics and mediator variables that best predict visitor responses to aircraft noise. The dose variables identified include sound exposure level, percent time audible, and energy percentages due to helicopters and fixed-wing propeller aircraft. Mediator variables identified include visitor ratings of the ‘importance of calmness, peace and tranquility’, attributes of adults-only in group, first visit to the site, having taken an air tour, and participation in activities of watching birds and listening to an interpretive talk. The models developed can be used as a tool for evaluating potential effects of air tours on visitors to National Parks.]]></description>
      <pubDate>Thu, 29 Dec 2016 17:03:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/1440556</guid>
    </item>
    <item>
      <title>A Research on City Street Stillness of Transit Mall</title>
      <link>https://trid.trb.org/View/1427827</link>
      <description><![CDATA[In this study, it was carried out noise measurement in the streets of transit malls (TM), streets with old tram tracks, and other city streets without any Trams. Equivalent sound levels (L eq) were calculated by the results of the field works. And distributions of sound pressure level were analyzed. Accordingly, followings have come to light as a result of this research. L eq of TMs are quieter than roads with two or four lanes. They are about the same as the noise level of daytime shopping street. If roadside is calm, even Japanese street with tram tracks is basically quiet. But its L eq is not necessarily low because of the noisy old tram tracks and the loud streetcars. There is not a clear difference between light rail transit (LRT) and bus rapid transit (BRT), but there is a tendency that Leq of transit malls of BRT are lower than streets with LRT because light rail vehicles (LRV) make some huge noise. 本研究では，実際にトランジットモールが実施されている街路および比較参考用に日本の路面電車の走行する街路やその他の街路で騒音測定を行い，等価騒音レベルを計算するとともに音圧の分布を分析した．その結果，TMの静寂性について以下のようなことがわかった．　トランジットモールにおける騒音レベルは，等価騒音レベルで見ると2車線や4車線の道路沿道レベルより静かであり，昼間の商業地の騒音レベルと同程度である．路面電車の走行している日本の街路についても，沿道が静穏であれば基本的には静かであるが，軌道や電車が古いために等価騒音レベルで見ると必ずしも静かでは無い． LRTとBRTとでは，明確な差は無いが突発的な大音量が発生しにくいためにBRTの方が等価騒音レベルは小さい傾向にある．日本の繁華街の街路は幹線国道でなくとも騒々しく，2車線道路や4車線道路の沿道レベル（70dB前後）と同程度である．]]></description>
      <pubDate>Mon, 21 Nov 2016 13:24:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1427827</guid>
    </item>
    <item>
      <title>Bayesian Traffic Light Parameter Tracking Based on Semi-Hidden Markov Models</title>
      <link>https://trid.trb.org/View/1429269</link>
      <description><![CDATA[The previous studies have shown that optimizing the driving velocity profiles and route selection based on the availability of the traffic lights' operation information in a traffic network can significantly reduce the individual and cumulative energy consumption of on-road vehicles for the urban driving. In this paper, the authors propose an accurate and precise stochastic online estimation method of the parameters of the traffic lights operating at a piecewise constant period. In this paper, the authors first model the traffic lights with a semi-hidden Markov model (SHMM) and then develop the period measurement model governed by a unique noise model specific to the indirect traffic light period measurements. The proposed method solves the estimation problem in two stages: in the first stage, the authors determine the sequence of the Markovian states maximizing the probability given the measurements and the SHMM parameters; then, in the second stage, the autho update the period and state duration estimates based on the Bayesian tracking given the corresponding latest measurements. The simulation and real vehicle data results prove that the proposed method can accurately estimate the switching times and the period of the piecewise fixed-period traffic lights.]]></description>
      <pubDate>Mon, 21 Nov 2016 13:24:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1429269</guid>
    </item>
    <item>
      <title>The purpose of road traffic noise measurement</title>
      <link>https://trid.trb.org/View/1207407</link>
      <description><![CDATA[]]></description>
      <pubDate>Fri, 24 Aug 2012 22:25:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1207407</guid>
    </item>
    <item>
      <title>A visit to Europe and the UK in August 1979</title>
      <link>https://trid.trb.org/View/1206924</link>
      <description><![CDATA[During a brief overseas tour the author attended the international tyre noise conference at stockholm and made four technical visits.  Papers (including one by the author) and discussion at the conference revealed that the Australian Road Research Board (ARRB) research in this area is well directed and is presently at the forefront of current tyre/ road noise technology.  During the conference, tyre/ road noise was seen to be the major component of constant speed vehicle noise for all speeds down to as low as 25 km/h.  Also, low noise and high skid resistance were shown to be compatible road design objectives.  Research reported on the two most popular theories of tyre/ road noise generation, air pumping and tyre vibration revealed that while both mechanisms will occur simultaneously, the former is generally the more important.  This mechanism was seen to explain the low noise properties of porous friction courses.  Some overseas tyre/ road noise work has been hampered by poor experimental technique and neglect of several fundamental principles of acoustics.  A number of useful ideas for verifying overseas data under Australian conditions and for improving the ARRB tyre/ road/ vehicle noise research program were formulated (a).]]></description>
      <pubDate>Fri, 24 Aug 2012 22:01:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/1206924</guid>
    </item>
    <item>
      <title>Recent Australian tyre/ road noise research</title>
      <link>https://trid.trb.org/View/1206670</link>
      <description><![CDATA[Recent Australian research by the author has concentrated on tyre/ road noise and the mechanism(s) by which it is generated.  In this paper the research is described and the results ensuing from it discussed in detail. Two fundamental research projects are covered in the paper.  The first of these is a laboratory study of the air pumping mechanism of tyre noise generation. Frequency spectra and directivity patterns were measured as the tyres were run on a drum roller in an anechoic chamber.  To complement these data, high speed movie photographs of tread pattern deformations in the tyre/ road contact zone were made as the test tyres were driven over a transparent glass plate.  On further analysis these tread deformation data were correlated with the noise data to provide a more detailed understanding of the air pumping mechanism. The second research project discussed in the paper concerns the measurement and analysis of passby noise data in determining some effects of road surface macrotexture on tyre/ road noise.  Using techniques pioneered in Europe and the USA, passby noise data have been collected for one vehicle and a variety of road surface macrotextures, tyre tread designs and vehicle speeds.  The results are discussed and compared, where possible, to those available from other countries.  A simplified, air pumping based model has been derived which successfully described some of these data (a).]]></description>
      <pubDate>Fri, 24 Aug 2012 21:53:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1206670</guid>
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