EVALUATION OF THE PERFORMANCE OF A ROAD SURFACE GONIOREFLECTOMETER

The reflection properties of the road pavement depend on the material and the texture of its surface. They can be specified with a set of luminance coefficients, which can be measured thanks to a gonioreflectometer. We presented in a previous paper a gonioreflectometer designed for in-lab measurements, especially suited for public lighting applications. We present in this paper a metrological evaluation of this instrument. First, we compare measurements from the gonioreflectometer with measurements taken with an illuminancemeter and a luminancemeter. Then we look at measurements in two analytically tractable cases. Finally, we perform uncertainty calculations on the luminance coeff icients, and extend the results to the road lighting application by calculating uncertainties on the lightness and specularity parameters. We also evaluate the influence of uncertainties on the performance of a given lighting design for two types of road surfaces. Our results indicate that the achieved uncertainties have a limited influence.