ASTM E1501-99(2004)

1.1 This specification covers the performance of retroreflective markings to be used on objects worn by pedestrians for the purpose of enhanced conspicuity. It addresses conspicuity from viewpoints around the entire object, and it allows for freedom of design of the markings so long as the minimum requirements are achieved. Objects include but are not limited to jackets, shirts, vests, trousers, socks, backpacks, hats, and footwear. An adjustment for the brightness/luminance ratio as a function of color is also made.

1.2 This specification applies only to nighttime viewing conditions in which the observer is positioned near a source of illumination. The most common example is that of a motor vehicle operator seeing by means of the light from the headlamps of the vehicle.

1.3 This specification describes the minimum retroreflective performance required for a reasonable level of nighttime conspicuity. It does not address potentially diminished performance of retroreflective markings that may be experienced with general storage, use, wear, and care.

1.4 SI (metric) units shall be used in referee decisions under this specification.

1.5 The following safety hazards caveat pertains to specifying materials by this standard specification. Although the markings described in this specification are intended to significantly enhance safety through increased conspicuity under most conditions of illumination and viewing of the type described in 1.2 above, they do not guarantee significantly enhanced conspicuity under all such conditions. Individuals exposed to adverse weather conditions or associated with high levels of vehicular or hazards exposure may require other types or amounts of retroreflective markings. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.