Because red light travels the farthest in the spectrum, red light also has a warning effect. Under normal field of view, red is the farthest band in the spectrum, which can be seen at a long distance, and the penetration is very strong, and it can be clearly seen on foggy and rainy days. Therefore, the red width indicator light and brake light use the characteristics of the red light wavelength to clearly inform the rear vehicle of its own location and increase the road safety factor. In addition to spreading far, red will also play a warning role, when you see the red taillights of the vehicle in front will attract the attention of the rear driver, and at the same time, the international use of red as a warning. Therefore, the taillights of the car are all red.
