1.1 本试验方法包括使用可现场使用的便携式反光仪测量交通标志和符号（垂直表面）等标志材料的反光性能。便携式回复反射仪是一种具有定义的标准几何形状的手持式仪器，可以放置在与标志材料接触的位置，以测量标准几何形状中的回复反射。可以将测量值与最低要求进行比较，以确定是否需要更换。本试验方法中规定的入射角和观察角为美国目前使用的入射角和观察角，可能与世界其他地方使用的角度不同。 1.2 本试验方法旨在用于交通标志的现场测量，但可用于在现场放置标志或在标志面上放置标志材料之前测量材料的性能。 1.3 本试验方法涵盖0.2度观察角度下的测量。见测试方法 E2540 用于0.5度观察角度的测量。 1.4 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。 1.5 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 通过本试验方法进行的测量与反光交通标志的夜间亮度有关，反光交通标志大致朝向配备钨丝前照灯的中型汽车驾驶员，距离约为200 m。 5.2 交通标志上使用的反光材料会随着时间的推移而退化，需要定期测量，以确保反光性能为驾驶员提供足够的安全性。 5.3 标志的质量（如所用材料、年龄和磨损模式）将对反射系数产生影响。用户需要观察和记录这些情况。 5.4 当仪器入口和观察角度与本文规定的不同时，本试验方法不用于测量标志。

1.1 This test method covers measurement of the retroreflective properties of sign materials such as traffic signs and symbols (vertical surfaces) using a portable retroreflectometer that can be used in the field. The portable retroreflectometer is a hand-held instrument with a defined standard geometry that can be placed in contact with sign material to measure the retroreflection in a standard geometry. The measurements can be compared to minimum requirements to determine the need for replacement. Entrance and observation angles specified in this test method are those used currently in the United States and may differ from the angles used elsewhere in the world. 1.2 This test method is intended to be used for the field measurement of traffic signs but may be used to measure the performance of materials before placing the sign in the field or before placing the sign material on the sign face. 1.3 This test method covers measurements at a 0.2 degree observation angle. See Test Method E2540 for measurements at a 0.5 degree observation angle. 1.4 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. 1.5 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 Measurements made by this test method are related to the night time brightness of retroreflective traffic signs approximately facing the driver of a mid-sized automobile equipped with tungsten filament headlights at about 200 m distance. 5.2 Retroreflective material used on traffic signs degrades with time and requires periodic measurement to ensure that the performance of the retroflection provides adequate safety to the driver. 5.3 The quality of the sign as to material used, age, and wear pattern will have an effect on the coefficient of retroreflection. These conditions need to be observed and noted by the user. 5.4 This test method is not intended for use for the measurement of signs when the instrument entrance and observation angles differ from those specified herein.