Fog lights are the most commonly used additional lights for off-road vehicles. Their characteristics are light scattering, wide illumination range, short distance, slightly yellowish light, low brightness, but strong ability to pass through rain, fog and dust. If driving in thick fog, the fog itself has a diffused light effect. When a car's headlights illuminate thick fog, the light scatters, forming a white barrier. In such foggy conditions, oncoming vehicles are not easily spotted. Its existence will cause a certain degree of danger. However, the yellow light of fog lights is more easily absorbed by fog than white light, giving drivers a better sense of distance and providing a clearer driving view.