The **front fog lights** are a type of lighting that helps improve visibility in adverse conditions such as fog, snow, heavy rain, and smoke. However, they are **not mandatory** for motor vehicles. This means that not all vehicles are required to have them installed or to use them in specific situations.

- Front fog lights can be white or yellow and are used together with the position lights. They can also be used together with the high and low beam lights, but their use is not mandatory in any specific circumstance.

- In contrast, the **low beam or dipped headlights** do have mandatory use in certain situations, such as at night or when driving through tunnels. This highlights that not all vehicle lights have the same level of obligation.

Therefore, although front fog lights are useful in certain weather conditions, they are not a legal requirement for all vehicles.