If you've ever driven in thick fog, you no doubt know not to use your car's high beam headlights. That's because regular headlights shine directly into the fog, bouncing the light right back at you, making it more difficult to see.
That's where fog lights come in. As the name implies, your car's fog lights are intended to be used so that you can see better while driving in heavy fog, mist, snow and even sand and dust, according to Lifewire. Fog lights are different from regular headlights, which have high-beam and low-beam functions.
The difference lies in their shape. They are bar-shaped and aimed sharply toward the ground, providing short-range visibility only just in front of your vehicle, according to Lifewire. By contrast, regular high- and low-beam lights aim straight ahead, lighting up the road to a further distance. When it's foggy, that light reflects back into your eyes, making it difficult to see. By aiming downward, fog lights eliminate this glare, allowing you to see better in fog.
It's important to note that, because fog lights provide light for only a short distance in front of your car, you should always drive more slowly when using them, which you should do in limited-visibility situations anyway.
There are other driving situations where using your regular headlight's low-beams can help improve visibility. Driving in rain can also cause light reflection, according to the Department of Motor Vehicles. If you drive in the city at night, low beams provide sufficient short-range visibility, which is all you need in urban driving.
Additionally, when another vehicle is approaching from the opposite direction at night, you'll want to switch to your low-beams so as not to blind the other driver. The same applies while driving behind another vehicle at night.