Need explanations for various different colors of a tail light
I have never paid attention to different colors that a car's tail light has. Today, when I was trying to check my 300SD's tail lights' bulbs, I noticed that there are 3 different colors: RED, ORANGE and WHITE.
For either the left or right tail light, the order of these colors are as follows (counting from outside to inside):
|red|orange| red |white|red|
I know that the big middle red is for darkness illumination and brake light (it has 2 different bulbs of 21W with a reflector, and 10W). The red area of the left (above drawing) is also for darkness illumination (10W bulb). However, I don't know what the purposes of the orange area, the white area, and the red area on the right side (above drawing) are. There is a 21W bulb in the orange area, a 21W bulb in the white area and no bulb in the red area on the right side. The strange thing is that I never saw the bulbs in the orange and white areas lighting up.
Could someone explain the purpose of each color?
Thanks a lot.