LED emits blue light originally, and it achieves white light by applying phosphor in the lamp shades. The color produced is a cold white. There are ways to change the color temperature to warm white, but these methods will add to the cost. One of the methods is adding phosphor, which may cause a loss of light. Another is to change the common LED street lights to RGB ones and then control the color temperature. Jedoch, RGB LED street lights are more expensive and not widely used.
Mehr Lektüre: Entwicklungsstadium und Farbtemperatursteuerung von LED-Straßenlichtern
