Relative Method of Measuring Coefficient of Luminous Intensity of Retro Reflective Devices

A relative method is proposed for measuring the coefficient of retro reflective light intensity CRLI through specific coefficient of retro reflective Luminance CRL and area of controlled product. In contrast to the adopted absolute measurement method, by measuring the ratio of light intensity of retro reflective sample to illuminance on it, it is proposed to measure reflectance of retro reflective sample in a small solid angle with calculation CRLI. The proposed method allows using the same testing unit and instruments for measuring CRLI, which are used to measure the CRL road signs and road markings. That permits to significantly reduce measurement error.