1.1 This practice covers the selection and use of a portable retroreflectometers for the measurement at a prescribed geometry of the retroreflective properties of horizontal pavement marking materials containing glass spheres, such as traffic stripes and surface symbols.

1.2 The entrance and observation angles provided in the retroreflectometer greatly affect the test results and must be a major consideration in the selection of the instrument. Information on the relationship between instrument geometry and viewing geometry is provided in Section 5. Information on viewing geometry is provided in Table 1. Information on the relationship between viewing geometry and coefficient of retroreflected luminance, RL is given in fig. 1.

1.3 This practice is intended to be used for selection of portable retroreflectrometers for field measurement of pavement markings but may also be used to select portable retroreflectometers to measure the performance of materials on sample panels before placing the marking material in the field.

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 and health practices and determine the applicability of regulatory limitations prior to use.