Brightness sensitivity of coloured led display in fog condition

Evaluation of the brightness sensitivity of coloured LED displays on traffic information boards in fog condition is an important practical consideration, because LEDs becomes faint and reduces contrast. Light scattering in fog is one of the most critical factors affecting human visual performance. To prevent this problem, it is necessary to study how fog effects human visibility. Inside of fog, LEDs of 12 colours were observed at five different fog densities and droplet sizes. The results show that reddish yellow from LED display is the brightest and blue light is the faintest. These results will contribute to land traffic and to the prevention of accidents in fog.