Abstract: The sound radiation model of the moving point source, single vehicle in a semi-free acoustic field is obtained for the research of road traffic noise. The acoustic characteristics of the noise radiated from single vehicle in real road conditions, such as sound level, signal in time domain, spectrum and sound quality etc., are discussed by means of noise measurements and related acoustic evaluations. The results show that the sound level radiated from single vehicle changes nonlinearly, i. e. increases first and then decreases with the distance from the vehicle to testing spot. The sound level of high frequency component attenuates more and more remarkably as the distance increases. Low frequency components with higher level are more predominent for the noise of middle and heavy car than that of small car. Regarding loudness the contributions at 125 Hz and 1 kHz for small car and that at (250～500) Hz for heavy car are predominant.

Key words: acoustics , traffic noise , noise assessment value , sound quality

摘要： 以道路通行的单个车辆为研究对象，导出半自由场单车点声源的噪声辐射模型，应用噪声测量分析手段，结合相应的声学评价量，对实际道路条件下单车辐射噪声的声级大小、时域信号、频谱、声学品质等特性进行探讨和研究。结果表明，随车辆与测点距离的变化，单车辐射声的声级呈现先增大后减小的非线性变化规律；其高频声压级随距离增加而衰减；与小车相比，中车和重车辐射噪声中的低频成份比例大，声级值高；小车辐射声响度在低频125Hz和高频1kHz频段的贡献量较大，重车则体现为低频段（250~500 Hz）贡献量大，而高频段的贡献量不明显。

关键词: 声学, 交通噪声, 噪声评价量, 声品质