Traffic Signal Feature
In addition to the general requirements for traffic lights, signal lights should also meet the following requirements:
① The light-emitting surface has a certain diameter, which is divided into 200mm and 300mm, and the surface brightness should be as uniform as possible.
②There are three light colors of red, yellow, and green, and sometimes white is also used.
③Use hat brim and other measures to reduce the false display phenomenon when sunlight is obliquely shining on the light emitting surface of the lamp.
For traffic signal lights that emit a single color, it is required:
①Light intensity: When the background brightness is 104cd/m2 and the viewing distance is 100m, the red light is 200cd, and the recommended ratio of red, yellow and green light intensity is 1:1.3:5. Except for urban highways and cities with bright backgrounds, the light intensity at night can be lower, so two light intensities of 200cd and 50cd can be used.
②Light intensity distribution: The light distribution is symmetrical. The light at the point where the light intensity drops to 50% of the peak light intensity should be at 10° to the left and right of the optical axis and 5° to 7° below the optical axis.