Mercedes-Benz S350 Rear Fog Light Only Lights Up on One Side

[DiElias]

In EU regulations, there is a little-known stipulation that if a vehicle is equipped with two rear fog lights, they must be positioned at least 10 centimeters away from the brake lights. However, this regulation doesn't seem to be enforced domestically. The reason for this distance requirement is that when rear fog lights are too close to the brake lights, following vehicles may easily confuse the two, interpreting the illumination of both lights as the preceding vehicle braking, which could potentially lead to traffic accidents. On the other hand, there's a rationale behind having only one rear fog light illuminated. It helps following vehicles better distinguish between the rear fog light and the brake light. Moreover, using just one rear fog light often enhances the attention of drivers behind, making it easier for other vehicles to notice the preceding car. As for why it's the left rear fog light that's typically illuminated rather than the right one, in China, where traffic keeps to the right, the driver sits on the left side.