The main reason why fog lights and high beams cannot be used simultaneously lies in the fundamental differences in their design functions and usage scenarios, and turning them on at the same time may cause serious safety hazards. Fog lights are specifically designed for low-visibility weather; their light has extremely strong scattering and penetration properties, mainly used for short-distance road illumination and warning surrounding vehicles, while the high-brightness red light source of rear fog lights is more easily recognized by vehicles behind in fog or haze. High beams, on the other hand, are used for long-distance straight-line illumination on unlit roads, with concentrated and high-intensity light. In addition, the combined use of fog lights and high beams will result in excessive illumination, which not only fails to improve the field of vision but also causes a glare effect on oncoming or front drivers, increasing the risk of judgment errors. According to traffic regulations, when visibility is less than 200 meters, high beams must be turned off and fog lights turned on, while the vehicle speed should be controlled below 60 kilometres per hour and a safe following distance of more than 100 meters maintained. The correct approach is: only turn on fog lights with low beams in foggy weather; if visibility is less than 50 meters, the hazard warning flashers should also be turned on simultaneously, and the highway should be exited as soon as possible. Special attention should be paid in daily driving: the abuse of fog lights is strictly prohibited in clear weather or when the lighting is good at night, so as not to interfere with other road users.
