Standard Test Method for Measuring the Coefficient of Retroreflected Luminance (RL) of Pavement Markings using the Bucket Method in a Condition of Wet Recovery

Importancia y uso:

4.1 The nighttime performance of pavement markings is determined by the coefficient of retroreflected luminance, R_L, be it dry or wet, and depends on the materials used, age, and wear pattern. These conditions shall be observed and noted by the user.

4.2 Under the same conditions of headlight illumination and driver’s viewing, larger values of R_L correspond to higher levels of visual performance at corresponding geometry.

4.3 The pavement marking’s measured performance in the condition of wet recovery is used to characterize the performance of the marking on the road when wet.

4.4 Newly installed pavement markings may have a natural surface tension or release agents that prevent wetting of the product by water. The water will tend to “bead up” on the marking. This “non wetting” condition is usually short lived. Pavement markings that have been on the road for one month prior to testing usually do not exhibit this non-wetting phenomenon. (Warning—This phenomenon produces an interference when assessing the wet characteristics of a pavement marking. Attempts to measure markings with this surface “non-wetting” or “beading” of the water may give higher values.)

4.5 The retroreflectivity, R_L, of pavement (road) markings degrades with traffic wear and requires periodic measurement to ensure that sufficient line visibility is provided to drivers.

4.6 For a given viewing distance, measurements of R_L made with a retroreflectometer having a geometry corresponding to that viewing distance are a good indicator of the visual ranking of the material measured.

4.7 As specified by Test Method E1710, the measurement geometry of the instrument is based on a viewing distance of 30 m, an eye height of 1.2 m and a headlight mounting height of 0.65 m (see Appendix X1).

4.8 It shall be the responsibility of the user to employ an instrument having the specified observation and entrance angles.

Subcomité:

E12.10

Referida por:

E2832-12R17, D8367-21

Volúmen:

06.01

Número ICS:

93.080.20 (Road construction materials)

Palabras clave:

dry retroreflection; mobile retroreflectometers; pavement markings; portable retroreflectometer; retroreflection in wet conditions;