Headlight refer to the lighting devices installed on both sides of the car's head and used for road traffic at night. There are two-light and four-light systems. The lighting effect of headlights directly affects the operation and traffic safety of driving at night, so the traffic management departments of various countries in the world generally stipulate the lighting standards of automobile headlights in the form of laws to ensure the safety of driving at night.
1. Requirements for the lighting distance of headlight
In order to ensure driving safety, the driver should be able to identify any obstacles on the road within 100m in front of the car. The lighting distance of the car high beam is required to be greater than 100m. This data is based on the speed of the car. As the speed of modern cars increases, the requirements for lighting distances will increase. The lighting distance of the car's low beam is about 50m. The location requirements are mainly to illuminate the entire road within the lighting distance and not deviate from the road.
2. Anti-glare requirements for headlight
The headlights of automobiles should be equipped with anti-dazzle devices to avoid traffic accidents caused by dazzling the driver of the opposite car when two cars meet at night. It is used when two vehicles meet at night, and the beam is inclined downward to illuminate the road within 50m in front of the vehicle, so as to avoid dazzling drivers of oncoming vehicles.
3. Requirements for the luminous intensity of headlight
The luminous intensity of the high beam of the car in use is: not less than 15000cd for the two-lamp system and not less than 12000cd for the four-lamp system;
With the development of high-speed vehicles, some countries have begun to experiment with three-beam systems. The three-beam system is high-speed high beam, high-speed low beam, and low beam. When driving on the highway, use the high-speed high beam; use the high-speed low-beam when driving on the road without oncoming vehicles or when meeting vehicles on the expressway, and use the low-beam when there are oncoming vehicles and urban traffic.