What is the 5'7" lighting rule?

The "5'7" lighting rule" refers to the standard irradiation height of low-beam headlights when driving at night, which should be controlled within the range of 0.4 to 0.8 meters (approximately 5.7 inches to 7.9 inches) from the ground. It is best to use level 0 when the vehicle is unloaded (with the light beam approximately 0.7 meters above the ground), and gradually increase the level to lower the beam height as the load increases. For instance, when fully loaded, adjust to level 3 to ensure the light beam does not exceed the eye level of oncoming drivers within 25 meters, thereby avoiding glare. For precise adjustment, the wall projection method can be employed: park the vehicle 7.6 meters from a wall, mark the 0.4-0.8 meter range, and align the lower edge of the light spot with the marked line. Within this height range, low-beam headlights can clearly illuminate the road 30-40 meters ahead (meeting the braking distance requirement at 55 km/h) without disturbing other road users. In special conditions such as rain or fog, fog lights should be used in conjunction, while high-beam headlights must be avoided to prevent light scattering.