Measuring retroreflected chromaticity coordinates of retroreflective sheeting

Retroreflective sheeting dramatically increases the visibility and conspicuity of traffic safety facilities at night. Chromaticity is an important property of retroreflective sheeting, but there are few methods and tools for measuring retroreflected chromaticity coordinates of retroreflective sheeting in China In this paper, measurement methods are introduced and the accuracy of portable equipment is analyzed. A spectroradiometric retroreflectometer system of the National Center ofMetrization for Equipments ofRoads and Bridges (NCMERB) and various portable equipment of testing agencies were selected. All instruments measured the chromaticity coordinates of the same set of samples. The data of the spectroradiometric retroreflectometer system were taken as the reference values and those of portable equipment as the comparison values. The results showed that the measurement deviations of a RoadVista 932 retroreflectometer were relatively small and that it can measure retroreflected chromaticity coordinates of retroreflective sheeting. The illuminating-viewing conditions may have little effect on the retroreflected chromaticity coordinate measurement results of yellow and red retroreflective sheeting.