New ASTM standards for reflectivity measurement.

A new standard test method, which measures the daytime performance of highway pavement markings in the field or laboratory, is available from ASTM International Committee E12 on Color and Appearance. E 2302, Standard Test Method for Measurement of Luminance Coefficient Under Diffuse Illumination of Pavement Marking Materials with CEN-Prescribed Geometry Using a Portable Reflectometer, is used to evaluate horizontal road stripes, symbols, and pavement surfaces.

According to the chair of the ASTM Subcommittee, Dennis Couzin, the luminance coefficient [Q.sub.d] in E 2302 provides the lighting performance of horizontal markings, or surfaces in a particular viewing direction. The diffuse illumination approximates daylight illumination from the overcast sky or road lighting. Participants in the ASTM retro-reflection subcommittee included major instrument makers from the U.S. and Europe.

The ASTM subcommittee welcomes input as it develops additional test methods that measure daytime and nighttime chromaticity of pavement marking materials with a portable reflectocolorimeter for more accurate measures of reflectivity. Highway retroreflective markings are much brighter than paint and, according to Mr. Couzin, are "optically tricky" materials, frequently comprised of small glass spheres embedded in a white or colored binder.

According to Mr. Couzin, the daytime chromaticity method under development requires approximately realistic measurement geometry, including diffuse illumination and near grazing detection. The new test method for nighttime chromaticity of pavement marking will allow various color detection methods in situ, crucial to measuring nighttime performance.

ASTM standards are available by contacting 610.832.9585, [e-mail], www.astm.org. For further technical information, contact Mr. Couzin at 847.588.7261, [e-mail].