• Journal of Environmental Science International
• /
• v.16 no.7
• /
• pp.823-830
• /
• 2007

Traffic noise is a kind of noise caused by cars, trains and aircraft. Among them, noise produced by cars is the most important factor in cities. According to the National Institute of Environmental Research(NIER)'s survey, Road traffic noise levels in Susan are the highest of all the cities in Korea. So, appropriate measures for road traffic noise reduction is required. For this purpose, the construction of a noise map in Susan will playa vital role. However, road traffic noise formulas are constructed considering regional characteristics such as each country road's environment and vehicle quality. Therefore, prior to constructing a noise map in Susan, examination processes about each formula constituent status and estimation process are required preferentially. In this research, the basic first stage is to estimate Susan's road traffic noise. First, investigate characteristics of each road traffic noise estimate and using this, a noise map is constructed for road traffic noise in Susan. Then the adaptation of a road traffic noise formula is evaluated.

• International Journal of Highway Engineering
• /
• v.17 no.4
• /
• pp.63-68
• /
• 2015

PURPOSES : A study on the efforts to minimize the road traffic noise has been underway. An attempt has been made to measure the noise level using a noise map; however, the attempt is limited to certain areas only. In general, a noise barrier is employed to prevent road traffic noise; however, unplanned noise barriers developed without considering the surrounding environment, including excessively high walls, cause problems such as infringement on prospect right. Noise ceiling at daytime in Korea is 68 dB(A), which is relatively higher than in other countries. METHODS: The noise barrier used mainly for road noise reduction was analyzed to estimate the optimal height. Related variables such as road width, the height of the upper part, distance to the building, and angle (for instance, $30^{\circ}$). RESULTS : A formula to calculate the optical height of the noise barrier, considering the road environment (i.e., parameters such as road width and distance to building), was developed in this study in an attempt to mitigate the noise generated from the road. CONCLUSIONS : The formula to calculate the noise barrier is expected to lead to cost saving, accurate installation of barriers, and protection of the right of prospect.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1D
• /
• pp.1-11
• /
• 2006

This study conducts a theoretical research on road traffic noise. Also, the domestic road noise forecast models were compared each other and analyzed with advanced countries' models to indicate the application possibility and problems. For the establishment of a general formula, we compared the forecasted value with the actual value applied in the formula proposed by the National Environment Institute, and examined the necessary improvement of the domestic road traffic noise forecast model. Also, a regression model was built to examine the relationship between traffic factors and noise. The traffic volume and speed are the main traffic factors used in this formula to affect the noise. From the results, it was found that the speed had a closer relationship with the noise rather than the traffic volume. Therefore, to decrease road noise, it is more important to control traffic speed. The spatial effect of road traffic noise within the apartment complexes was used in the case study to derive location-specific adjustment values. We surveyed the road traffic noise of three apartment complexes, and found that the road traffic noise within each complex was affected at plane level as well as at three-dimensionally. In other words, as the distance from the sound origin grows farther, noise level decreases. Also, it was found that noise increases as heigt goes up, but drops when the height goes beyond a certain level, and that the effect of noise decreases if there are obstacles along the path of the noise direction. Therefore, apartment site design should be done with consideration of the effects of noise in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.303-310
• /
• 2008

In Korea, the current noise impact assessment has not yet considered the vertical noise propagation property by buildings and other obstacles. And noise control plan has been established without conducting the economic assessment for the noise control facilities. A noise map is used to calculate the noise level based on a theoretical formula or an empirical formula, and also predict the characteristics of vertical propagation by linking with a geometry data. And It is Possible to analyze cost-effect of noise control facilities by consider installation costs. In this study, we addressed the application of noise map for noise impact assessment and cost-effect analysis of noise control facilities.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.6 s.99
• /
• pp.635-644
• /
• 2005

This paper is. a study on relation between road traffic noise(RTN) and sound power level(PWL). At present, many experimental formulae and prediction formulae are used for prediction of RTN. But these formulae are difficult to appiy to the metropolitan area because these formulae are inaccurate in the different condition from reference condition. This paper calculate RTN and PWL of each prediction formula, choose the best one and make a noise map of the subject area. Procedure is as follows. First, calculate $L_{eq}$ of RTN using experimental formulae and prediction formulae. Second, calculate PWL using $L_{eq}$ of RTN and distance attenuation for point source at semi-free field. Third, choose the most accurate formula. And finally, make a noise map of the subject area at present and future. The result using noise map will be able to apply to application field. Noise mapping tool used on this paper is Raynoise program using Ray Tracing Method(RTM), Mirror Image Source Method(MISM) and Hybrid Method(HM).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.641-648
• /
• 2006

This study investigates which sound quality indices except SPL raise annoyance response. For investigation, auditory perception experiments for road traffic noise with identical linear SPL were performed by Paired Comparison Method. The numerical results of a Paired Comparison experiment express relative preference about annoyance. So that these relative preference scores are to be correlated to sound quality indices, which are absolute, a transformation is required to go from the relative domain to an absolute and linear scale of preference. The results of the transformation will be the 'merit values,' which quantifies the annoyance(in this case) of the road traffic noise on a linear scale. Using multiple regression, a formula is established that can calculate predicted merit values. Furthermore, This investigation offers a method selecting sound samples that represent various sound quality indices values to use experiment.

• Journal of Environmental Impact Assessment
• /
• v.14 no.1
• /
• pp.25-36
• /
• 2005

Actually, prediction formula of road traffic noise for EIA(Environmental Impact Assessment) has been used that proposed by National Institute of Environmental Research in 1999. The prediction formula, however, was calculated predicted noise level according to noise level producing on first floor, then needs to correct noise level at each floor in the case of apartment building. The investigation was carried out to calculate the correction coefficient for commonly using in EIA of large scaled apartment development areas. The noised level at each floor were measured from August 2001 to March 2002 at 31 investigation points of large scaled apartment development area in national wide. Measured data were divided and treated with 4 types as 3th floor, 5th floor, 7th floor and 10th floor and then the correction coefficients of each floor were calculated using by correlation formula according to each floor.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.11
• /
• pp.1198-1206
• /
• 2006

We have carried out highway traffic noise prediction and measurement for 10 sites with representative road shapes and structures. A road traffic noise prediction model(NIER('99)) has been developed for environmental impact assessment in Korea. With the fitted regression analysis, the distribution ratio($R^2$) and Pearson correction coefficient(r) was 92.4% and 0.96 in $1^{st}$ floor, 38.7% and 0.66 in $3^{rd}$ floor, 42% and 0.65 in $5^{th}$ floor, 7.5% and 0.27 in $7^{th}$ floor, 28.4% and 0.53 in 10th floor, 35.6% and 0.60 in $13^{th}$ floor, 52.7% and 0.73 in $15^{th}$ floor, respectively. The measured values of the noise level except the 1st floor did not show a good agreement with the predicted noise level in the NIER('99) formula. Also, the NIER('99) formula demonstrated that the measured values weren't reasonably close to the predicted values, indicating the validity and adequacy of the predicted models with the fitted vs residual analysis in the 95% of confidence interval and 95% of predict interval. Using the equal variation on the basis of the residual vs fitted value, there was the significant difference for variation between $3^{rd}$ floor and $15^{th}$ floor except $1^{st}$ floor. The results suggested that the NIER('99) model obtained by the results according to the apartment floor must be improved and developed on the road traffic noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.11 s.116
• /
• pp.1124-1131
• /
• 2006

This paper presents a novel method to determine sound power level(PWL) emitted by a travelling vehicle for road traffic noise simulation. The PWL is evaluated by the equivalent sound pressure level (SPL) measured by close proximity method and the sound power correction factor derived from the maximum SPL measured by pass-by method and the propagation attenuation of vehicle noise during the pass-by measurement. Using the method, we derive the empirical formula for PWL estimation in 1/1-octave and overall frequency bands for 8 vehicles (automobile, SUV, small truck, large bus, trailer, 3 dump trucks) tested at two road surfaces (dense graded asphalt, 30mm transverse tinning concrete) of Korean highway test road. The suggested approach, if securing sufficient data to represent the acoustic characteristics of all vehicle types, has il strong merit to be able to evaluate sound power levels for any combination of vehicle categories and traffic volumes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.05a
• /
• pp.421-427
• /
• 2006

This paper presents a novel method to determine sound power level(PWL) emitted by a travelling vehicle for road traffic noise simulation. The PWL is evaluated by the equivalent sound pressure level(SPL) measured by close proximity method and the sound power correction factor derived from the maximum SPL measured by pass-by method and the propagation attenuation of vehicle noise during the pass-by measurement. Using the method, we derive the empirical formula for PWL estimation in 1/1-octave and overall frequency bands for 8 vehicles(automobile, SUV, small truck, large bus, trailer, 3 dump trucks) tested at two road surfaces(dense graded asphalt, 30mm transverse tinning concrete) of Korean highway test road. The suggested approach, if securing sufficient data to represent the acoustic characteristics of au vehicle types, has a strong merit to be able to evaluate sound power levels for any combination of vehicle categories and traffic volumes.