Prediction of Sound Attenuation of Road Traffic Noise During Propagation in Urban Area

本研究的目的是建立城市道路交通噪声传播过程中声衰减的预测方法。我们希望建立一种简单实用的方法来计算该地区道路交通噪声的宏观分布。因此，在这种预测方法中，计算时不考虑区域内每栋建筑的形状，而只考虑建筑物的密度。通过对实验数据的统计分析，提出了一种计算车辆噪声衰减的新方法。这一程序的概要如下。假设车辆与接收点的连接线为中心的矩形，并利用矩形中与建筑物密度有关的参数计算噪声衰减，然后对实际交通流量较大的5个路段的126个接收点的道路交通噪声进行了测量，以验证该计算方法的有效性。基本检验表明，道路交通噪声的衰减简单地取决于接收点与道路部分连接形成的三角形内建筑物的密度。我们现正根据上述方法，以电脑模拟方法计算道路交通噪音的衰减，这项研究仍未完成，但我们会尽快完成。

The aim of this study is to develop the method to predict the sound attenuation of road traffic noise during its propagation in the urban areas. We want to establish a easy and practical method to calculate macro-distribution of road traffic noise in the area. In this predicting method, therefore, shape of each building in the area is not taken into consideration for calculation but only density of buildings is taken.In order to carry out this study, model experiments were at first performed. By the statistical analysis of experimental data, a new method to calculate the attenuation of noise from a vehicle was proposed. The outline of this procedure is as follows. A rectangle where the line connected by a vehicle and a receiving point is center was supposed and some parameters concerning to the density of buildings in the rectangle was used to calculate the attenuation of noise.Next, in order to make clear the validity of this calculating procedure, road traffic noise was measured on one hundred twenty-six receiving points at five places along real roads with heavy traffic volumes. The basic examination showed that attenuation of road traffic noise simply depended on the density of buildings in a triangle made by connecting a receiving point with a part of road. Now we are calculating attenuation of road traffic noise by computer simulation based on the method mentioned above.We have not completed this study yet but we will do as soon as possible.