M5 등급 낮은조명 개발 및 기존 등주식 조명과 시지각적 성능 비교

PURPOSES : The purpose of this study is to introduce the development of M5 low-level lighting (LLL) with the necessity and justification, mainly the ecological traffic safety merits and the convenience and traffic efficiency of maintenance compared to the existing high mounted pole lightings. The basic photometric property of the developed facility is analyzed. The visual performance is analyzed in terms of visibility distance and subjective opinions from the subjects on several factors related to lighting performance. METHODS : The basic photometric properties of LLL were measured in a tunnel-shaped shield with a visibility meter (LMK 5 Color). The visibility distance between LLL and existing pole-based lighting was observed by 13 subjects under various weather conditions, such as dry, rainy, and wet conditions. In addition, the subjective opinions in terms of several pre-designed factors regarding lighting performance were surveyed. RESULTS : The developed M5 LLL satisfied photometric requirements such as average surface luminance, overall uniformity, and lane uniformity, as suggested by the lighting guidelines. More than 200 m of visibility distances were measured under normal weather conditions for both LLL and existing pole lightings. However, more than 200 m were observed under a wet surface and a rain intensity of 20 mm/h in the case of LLL, but visibility distance was reduced to 48.46 m in the case of pole lightings. A higher visibility distance was observed in the case of amber colored LLL. According to the results of the subjective opinion survey, all types of lightings had favored ratings, and the whitecolored LLL showed the highest ratings under normal weather conditions. However, existing pole lightings had unfavorable ratings under wet surface and rainy conditions, whereas the amber colored LLL had favorable ratings compared to pole lightings in terms of uniformity of illumination, glare, and psychological stability. CONCLUSIONS : The necessity of M5 LLL lies on the cost-effective application to the low standard roadways where the cost is always the main factor to consider in safety facilities and the ecological benefits of roadsides. The developed LLL satisfied the basic optical property suggested by the related lighting guidelines and showed higher performance in terms of visibility distance across various weather conditions compared to the existing high mounted pole lightings.