Required luminous intensity ratio of led road traffic signal lights.?testfor finding the luminous intensity ratio that ensures the same visibilityperformance of red, yellow, and green roundel lights.

The minimum luminous intensity values of traffic signal lights are provided as recommended values in the report of the commission internationale del'eclairage (international commission on illumination) (cie). japanese standards are based on these recommended values of cie. on the other hand, the luminous intensity ratio of the red, yellow, and green roundel lights is not yet made clear by cie. Therefore, a test was carried out to determine the luminous intensity ratio that ensures that all of the red, yellow, and green roundel lights of an led road traffic signal light provide the same visibility performance.