CONTRAST RATIO STUDIES OF A LED-FLASHED TRAFFIC SIGN AT A FOGGY ROAD

摘要

Systematic studies on the visibility of a traffic sign on an experimental road in a foggy environment were performed. We defined contrast ratios C_(pb) and C_(pS) as the level of fog and index of visibility of the traffic sign, respectively. The analysis of the experimental results show that C_(pS) of passive state of the traffic sign is proportional to C_(pb) for all varieties of luminaire and headlights. While C_(pb) of active state is linear with C_(pb) and the intercept and slope are fairly dependent on position and type of luminaire.