1.1 本规程描述了用仪器测量反光材料和反光装置光度特性的一般程序。 1.2 本规程是回复反射器光度测定的综合指南，但不包括实践中描述的几何术语 E808 . 1.3 本规程描述了在特定试验和回复反射器规范中说明光度测量时所需的参数。 1.4 以国际单位制表示的数值应视为标准值。 国际单位制后括号中给出的值仅供参考，不被视为标准值。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本规程描述了用于测量与反向反射光视觉感知相关的光度量的程序。最重要的用途是与夜间车辆前照灯、回复反射器和驾驶员眼睛几何形状有关。因此，CIE标准光源A用于表示钨车辆前照灯，并且接收器具有明视性， 五、 （λ） ，对应于光适应人眼的光谱响应度。尽管几何形状必须由用户指定，但通常它将对应于车辆前照灯、回复反射器和车辆驾驶员眼睛位置之间的关系。

1.1 This practice describes the general procedures for instrumental measurement of the photometric characteristics of retroreflective materials and retroreflective devices. 1.2 This practice is a comprehensive guide to the photometry of retroreflectors but does not include geometric terms that are described in Practice E808 . 1.3 This practice describes the parameters that are required when stating photometric measurements in specific tests and specifications for retroreflectors. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This practice describes procedures used to measure photometric quantities that relate to the visual perception of retroreflected light. The most significant usage is in the relation to the nighttime vehicle headlamp, retroreflector, and driver's eye geometry. For this reason the CIE Standard Source A is used to represent a tungsten vehicle headlamp and the receptor has the photopic, V (λ), spectral responsivity corresponding to the light adapted human eye. Although the geometry must be specified by the user, it will, in general, correspond to the relation between the vehicle headlamp, the retroreflector, and the vehicle driver's eye position.