本文件描述了一种测量交通降噪装置空气载声隔声固有特性代表量的试验方法:隔声指数。 试验方法适用于以下应用: -在现场或实验室条件下测定沿道路安装的降噪装置的空气声隔声固有特性； -实际使用中降噪装置的空气声隔声固有特性的现场测定； -施工工作完成后，将设计规范与实际性能数据进行比较； -验证降噪装置的长期性能（重复使用该方法）； -新产品的交互设计过程，包括安装手册的制定。 本试验方法不适用于测定在混响条件下安装的降噪装置的空气声隔声固有特性，如隧道内、深沟内或覆盖物下。 结果以三分之一倍频程的频率表示，可能的话，在100Hz和5kHz之间。如果无法在所示的整个频率范围内获得有效的测量结果，则应在限制的频率范围内给出结果，并明确报告限制的原因。

This document describes a test method for measuring a quantity representative of the intrinsic characteristics of airborne sound insulation for traffic noise reducing devices: the sound insulation index. The test method is intended for the following applications: - determination of the intrinsic characteristics of airborne sound insulation of noise reducing devices to be installed along roads, to be measured either in situ or in laboratory conditions; - determination of the in situ intrinsic characteristics of airborne sound insulation of noise reducing devices in actual use; - comparison of design specifications with actual performance data after the completion of the construction work; - verification of the long term performance of noise reducing devices (with a repeated application of the method); - interactive design process of new products, including the formulation of installation manuals. The test method is not intended for the determination of the intrinsic characteristics of airborne sound insulation of noise reducing devices to be installed in reverberant conditions, e.g. inside tunnels or deep trenches or under covers. Results are expressed as a function of frequency in one-third octave bands, where possible, between 100 Hz and 5 kHz. If it is not possible to get valid measurement results over the whole frequency range indicated, the results will be given in a restricted frequency range and the reasons for the restriction(s) will be clearly reported.