Why does the BMW X4 have only one rear fog light?

[William]

The reason there is only one rear fog light is that the rear fog light, along with the position lights and brake lights, are all red. To facilitate identification, only one rear fog light is installed, making it easier for following vehicles to notice. Introduction to rear fog lights: Having only one rear fog light allows following vehicles to distinguish that the front vehicle is using fog lights, ensuring safety. Due to their lighting characteristics, fog lights need to penetrate through fog in heavy fog conditions, being more intense and glaring to alert following vehicles promptly, so they require strong penetration and high visibility. Introduction to front fog lights: Front fog lights are not used for illumination but to provide a high-intensity scattered light source designed to penetrate thick fog and alert oncoming drivers. Front fog lights should not be used under normal conditions but only in heavy fog situations.