LED (Light Emitting Diode) is a new type of light source developed and produced. It has the advantages of low power consumption (current is only 10~20mA), high brightness (light intensity can reach tens of thousands of mcd), small volume (minimum diameter can reach 3mm), light weight (a light emitting diode weighs only a few tenths of a gram), long life (average life of 100000 hours), etc. Now it has gradually replaced incandescent lamps and low voltage halogen tungsten lamps to produce road traffic signal lamps.

Traffic signal lamps are divided into: motor vehicle signal lamps, non motor vehicle signal lamps, crosswalk signal lamps, direction indicator lamps (arrow signal lamps), lane signal lamps, flashing warning signal lamps, and road and railway intersection signal lamps.