Traffic Noise Model vs. Extreme Topography

2003 ◽  
Vol 1859 (1) ◽  
pp. 65-71
Author(s):  
Michael A. Staiano
Keyword(s):  
Traffic Noise ◽  
Severe Case ◽  
Sound Attenuation ◽  
Noise Model ◽  
Interstate Highway ◽  
Site Model ◽  
Sound Levels

Traffic noise exposures were measured at various locations adjacent to an Interstate highway and compared with sound levels predicted by the FHWA Traffic Noise Model (TNM). The prediction procedure underestimated the measured sound attenuation by 6 to 12 A-weighted decibels. Various TNM site model configurations were evaluated in an effort to improve agreement between measurements and predictions. For the site tested—a severe case with relatively distant receptors and extreme topography—variations in ground impedance (including a median ground zone) had little benefit or were counterproductive, while adding topographic detail via terrain lines helped somewhat. The best agreement resulted from the incorporation of a tree zone for the wooded site. However, this benefit is thought to be chance, because the site was not only relatively lightly wooded but also thinly foliaged at the time of the on-site measurements.

Simulation Approach to Traffic Noise Modeling: American Automobile Manufacturers Association Community Noise Model Version 4.0

1997 ◽  
Vol 1601 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Roger L. Wayson ◽  
John M. MacDonald ◽  
Ronald Eaglin ◽  
Barbara Wendling
Keyword(s):  
Simulation Model ◽  
Traffic Noise ◽  
The United States ◽  
Point Sources ◽  
Noise Model ◽  
Community Noise ◽  
Model Free ◽  
Sound Levels ◽  
Acceleration And Deceleration ◽  
Interrupted Flow

Several models are available for predicting traffic noise levels. The FHWA-promulgated model, STAMINA 2.0, is the most widely used noise model in the United States and is used to model free-flow vehicular traffic. STAMINA 2.0 cannot directly model interrupted-flow traffic. Sound levels from interrupted-flow traffic can be approximated with STAMINA 2.0 using the method presented in NCHRP Report 311. This method is time-consuming and difficult to use. These limitations demonstrate the need for a traffic noise model that can model the acceleration and deceleration behavior of interrupted-flow traffic. The University of Central Florida has developed the American Automobile Manufacturers Association Community Noise Model (CNM). The CNM is a traffic simulation model that determines sound levels at receivers by modeling vehicles as discrete moving point sources. The vehicle energy is determined from acceleration, deceleration, idle, and cruise reference energy mean emission level curves. Sound energy attenuation is calculated from distance, ground absorption, and user input barriers. The model sums the energy at receivers from all vehicles and then calculates the Leq noise level at the receivers. It is demonstrated that the CNM predicts receiver Leq levels that are very close to STAMINA 2.0 results for constant-speed traffic. The CNM can also accurately predict sound levels at receivers located before and after intersections. In addition to the advantages of a real simulation model, the CNM is user friendly, allowing the user to place lanes and receivers using the mouse.

Florida Noise Barrier Evaluation and Computer Model Validation

2003 ◽  
Vol 1859 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Roger Wayson ◽  
John MacDonald ◽  
Ahmed EI-Assar ◽  
Win Lindeman ◽  
Mariano Berrios
Keyword(s):  
Insertion Loss ◽  
Traffic Noise ◽  
Sound Level ◽  
Noise Model ◽  
Barrier Method ◽  
Noise Barriers ◽  
Zone Length ◽  
Sound Levels ◽  
Noise Barrier ◽  
Source Level

The results of a project that investigated the effectiveness of in situ noise barriers in Florida are presented. The prediction accuracy of the FHWA Traffic Noise Model (TNM) is compared with STAMINA 2.0 and 2.1 (Florida-specific). A total of 20 barrier sites were visited during a 3-year period that resulted in 844 discrete 20-min equivalent sound level (Leq) measurements behind the barriers. Barrier insertion loss was determined using the ANSI indirect barrier method. A methodology was developed to estimate shadow zone length created behind highway noise barriers. All of the barriers tested were effective (>5 dB:LAeq insertion loss at distances equivalent to the first row of homes, where LAeq is the A-weighted Leq) except one site because of marginal additional shielding from a berm–barrier combination. Only three sites had an insertion loss of less than 5 dB at distances representative of the second row of homes. Overall, measurements indicate that the barriers provide substantial sound level reduction for residents along the highway. TNM was the best prediction model when considering all test sites; however, the STAMINA models were more accurate at predicting source level. TNM predictions using the Average pavement input overpredicted the reference sound levels measured at these sites. TNM predictions using the OGAC (open-graded asphalt concrete) input were improved (under 2 dB:LAeq of error) over those using the Average pavement type input. This result is expected because Florida uses an open-graded asphalt friction mix.

Acoustic Modeling of Meteorological Effects on Roadway Noise

2021 ◽  
pp. 036119812199458
Author(s):  
Roger L. Wayson ◽  
Kenneth Kaliski
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Model Development ◽  
The United States ◽  
Noise Model ◽  
Road Traffic Noise ◽  
Atmospheric Conditions ◽  
Noise Propagation ◽  
Transportation Research ◽  
Meteorological Effects

Modeling road traffic noise levels without including the effects of meteorology may lead to substantial errors. In the United States, the required model is the Traffic Noise Model which does not include meteorology effects caused by refraction. In response, the Transportation Research Board sponsored NCHRP 25-52, Meteorological Effects on Roadway Noise, to collect highway noise data under different meteorological conditions, document the meteorological effects on roadway noise propagation under different atmospheric conditions, develop best practices, and provide guidance on how to: (a) quantify meteorological effects on roadway noise propagation; and (b) explain those effects to the public. The completed project at 16 barrier and no-barrier measurement positions adjacent to Interstate 17 (I-17) in Phoenix, Arizona provided the database which has enabled substantial developments in modeling. This report provides more recent information on the model development that can be directly applied by the noise analyst to include meteorological effects from simple look-up tables to more precise use of statistical equations.

scholarly journals Automotive traffic noise and urban public spaces

2021 ◽  
Vol 9 (72) ◽  
Author(s):  
Greicikelly Gaburro Paneto ◽  
Cristina Engel de Alvarez ◽  
Paulo Henrique Trombetta Zannin
Keyword(s):  
Urban Space ◽  
Sound Pressure ◽  
Traffic Noise ◽  
Motor Vehicles ◽  
Open Spaces ◽  
Sound Levels ◽  
Measurement Results ◽  
Sound Pressure Levels ◽  
High Sound

In contemporary cities, and usually without realizing it, the population has been exposed to high sound pressure levels, which besides causing discomfort, can lead to health problems. Considering that a large part of this noise comes from emission from motor vehicles, this research aims to evaluate the sound behavior in sound environments configured by voids in the urban fabric, in order to identify whether open spaces can act as attenuators of sound levels. To obtain the expected results, the methodology used was structured from a review of the state-of-the-art and computer simulations relating the variables that influence the formation of urban space and sound emission and propagation, taking as a case study an urban portion of the municipality of Vitória/ES. In parallel, questionnaires were applied to evaluate the user's perception of their exposure. The measurement results indicated that the sound pressure levels caused by traffic noise are above the limit tolerated limit by the NBR norm 10151:2000 for the daytime period. In turn, the results obtained from the population indicated that there is little perception of noise by the users of the spaces surveyed.

scholarly journals METHODUCAL APPROACH AND ASSESSMENT OF NOISE IMPACT OF RAIL TRANSPORT ON THE BASIS OF THE USE OF RISK ASSESSMENT METHODOLOGY

2019 ◽  
Vol 96 (7) ◽  
pp. 675-681 ◽  
Author(s):  
Olga I. Kopytenkova ◽  
D. E. Kurepin ◽  
K. B. Fridman ◽  
E. B. Kuznetsova
Keyword(s):  
Extreme Values ◽  
Residential Buildings ◽  
Traffic Noise ◽  
Calculated Data ◽  
Ground Surface ◽  
Field Measurements ◽  
Railway Transport ◽  
Sound Levels ◽  
Age Related ◽  
Zone Of Influence

The paper presents the results of measurement, prediction and assessment of noise in the territory in the zone of the influence of the railway transport. The railway transport is established to be a source of excess acoustic impact on the environment within the area of sanitary break (100 m). The dependence of the change in noise levels from freight trains at a distance of 100 m from the source and up to 30 m from the ground surface was revealed. Equivalent sound levels in octave bands for the railway section of the model are calculated. Based on the results of field measurements and calculated data, the identification of indices of risk for adverse reactions in the population living in the zone of influence of the Railways was executed. The paper presents results of the calculation of the probability of occurrence of complaints on excessive noise and the likelihood of irritation at the noise, and the results of the calculation of risk indices of pathologies of the nervous and cardiovascular systems. The research made it possible to identify the regulatory documentation discrepancy in the definition of the health gap between the line source traffic noise and residential buildings. Field measurements and executed on their basis their modeling of the noise propagation (without obstacles) have shown that on the boundary of the regulatory sanitary protection zone (100m) in the congested section of the railway the noise level of 60-62 dBA is maintained. The risk of irritation to the noise and the likelihood of complaints is assessed as “acceptable”. The risk of pathology of the cardiovascular system is evaluated as “low”. At a distance of 50 m (65 dBA) with bearing in mind age-related changes after 70 years of exposure the risk reaches of extreme values - 0,935. Construction sites located less than 100 m from the railway were shown to fall into the zone of acoustic discomfort. There was substantiated the necessity of resolving differences in regulatory documentation by harmonizing sanitary and technical groups documents regulating methods of measurement, prediction and evaluation of sound levels on the territories in the zone of influence of the Railways.

Comparison of Traffic Noise Model 2.5 with 2.1 and Measured Data

2005 ◽  
Vol 1941 (1) ◽  
pp. 149-154
Author(s):  
A. A. El-Aassar ◽  
R. L. Wayson ◽  
J. M. MacDonald
Keyword(s):  
Traffic Noise ◽  
Measured Data ◽  
Noise Model ◽  
Average Error ◽  
Matched Pairs ◽  
Federally Funded ◽  
Reference Measurement ◽  
Previous Version ◽  
Ground Effects ◽  
Predicted Values

Traffic Noise Model Version 2.5 (TNM 2.5) will soon be the official traffic noise model required by the FHWA for federally funded projects. TNM was updated from Version 2.1 to 2.5 to address two major issues: the overprediction found in the previous version of TNM and an anomaly related to diffraction points. This research focused on comparing the TNM 2.5 predicted results with TNM 2.1 predicted values and with measured data from 18 barrier locations in Florida. Matched pairs of predicted and measured differences between the data for TNM 2.5 and TNM 2.1 were evaluated and a direct comparison of the two models was made. This research demonstrated that the predicted results from TNM 2.5 had an average error for all 18 barrier locations of less than 1 dB. However, when each of the sites is evaluated individually, TNM 2.5 has a tendency to underpredict slightly at many of the evaluated barrier locations. Finally, TNM 2.5-predicted results tend to be about 3 dB(A) on average less than TNM 2.1 at a defined reference measurement position, which is relatively unaffected by ground effects or diffraction, and about 1 dB less at microphone positions behind evaluated barriers when compared with TNM 2.1.

scholarly journals Numerical Evaluation of Sound Attenuation Provided by Periodic Structures

2013 ◽  
Vol 38 (4) ◽  
pp. 503-516 ◽  
Author(s):  
Mário Martins ◽  
Luís Godinho ◽  
Luís Picado-Santos
Keyword(s):  
Periodic Structures ◽  
Traffic Noise ◽  
Fundamental Solutions ◽  
Sound Attenuation ◽  
Method Of Fundamental Solutions ◽  
Noise Sources ◽  
Noise Abatement ◽  
Acoustic Performance ◽  
Sonic Crystals ◽  
Different Sources

Abstract The use of periodic structures as noise abatement devices has already been the object of considerable research seeking to understand its efficiency and see to what extent they can provide a functional solu- tion in mitigating noise from different sources. The specific case of sonic crystals consisting of different materials has received special attention in studying the influence of different variables on its acoustic performance. The present work seeks to contribute to a better understanding of the behavior of these structures by implementing an approach based on the numerical method of fundamental solutions (MFS) to model the acoustic behavior of two-dimensional sonic crystals. The MFS formulation proposed here is used to evaluate the performance of crystals composed of circular elements, studying the effect of varying dimen- sions and spacing of the crystal elements as well as their acoustic absorption in the sound attenuation provided by the global structure, in what concerns typical traffic noise sources, and establishing some broad indications for the use of those structures.

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