A LABORATORY METHOD FOR OBTAINING PAVEMENT REFLECTANCE DATA

ILLUMINATING ENGINEERS HAVE LONG KNOWN THE IMPORTANCE OF PAVEMENT LUMINANCE IN ROADWAY DESIGNS. IT IS ALSO WIDELY KNOWN THAT PAVEMENT LUMINANCE DEPENDS ON THE RELATIVE POSITIONS OF THE OBSERVER AND THE LIGHT SOURCE AS WELL AS THE DIRECTIONAL REFLECTANCE CHARACTERISTICS OF THE PAVEMENT SURFACE. HOWEVER, AT PRESENT THERE IS LITTLE INFORMATION AVAILABLE THAT WILL PERMIT THE CALCULATION OF PAVEMENT LUMINANCE FROM AN ILLUMINATION SPECIFICATION. THIS PAPER DESCRIBES THE INSTRUMENTATION AND PROCEDURES ASSOCIATED WITH A LABORATORY METHOD FOR DETERMINING THE DIRECTIONAL REFLECTANCE CHARACTERISTICS OF PAVEMENT SURFACES. IN ADDITION, DATA COLLECTED FOR ONE TRAFFIC-WORN ASPHALT PAVEMENT SURFACE ARE PRESENTED. /AUTHOR/