Car headlight is the lamp that illuminates the road in front of the car when driving at night, it can emit two kinds of beams of light: far light and near light. High light is used when there is no traffic or when the car is traveling at a high speed. Far light should ensure that in front of the car 100m or farther on the road surface to get bright and uniform lighting. Short-cut light is used when meeting cars or driving on the city's bright roads. In order to avoid the danger of oncoming drivers blinding, headlights should turn the strong far light into the less bright and downward-dipping near light.