The four - lamp car must be fitted with two beam lights, far and near
Just one light bulb with two filaments on it
In order to solve in the meeting process, the headlight does not produce glare, but also can ensure good lighting on the road, in 1932 the United States invented the asymmetric headlight, which is based on the reference axis, the beam near the landing distance to One divides into two., side of the car (i.e. low pressure short beam, and anti dazzle) on the other side of the beam, and landing distance (i.e. long beam elevation, thereby increasing visibility).
The dual light head headlamp system belongs to symmetrical near light system, and the left and right sides of the near light type are identical. But as the driving light (Yuan Guang) changes to the vehicle light (near light), the distance of sight is shortened, forcing the speed to decrease.
