Fog Lights aren’t standard equipment on most new automobiles. They do seem to be an added feature on many deluxe car models, though, and you can always have them added on as an accessory on any vehicle. The question is: Do you really need them?

When do you use them?

There’s actually a lot of confusion out there on the subject of fog lights. Unlike high and low beam headlights, which drivers use all the time, fog lights are only useful in a few very specific situations. They are specifically designed for use in poor weather and other situations where visibility is reduced.

How do they work?

Many people think that fog lights are simply another set of lights, usually more powerful lights, that can help pierce through bad visibility conditions. While there is some truth to this, fog lights have another characteristic that makes them valuable to use. The basic argument is that standard headlights, particularly high beam headlights, tend to reflect off things like fog and snow, right back in a driver’s eyes. Sometimes if the conditions are just right, the reflection can be almost blinding and it doesn’t matter if you use high or low beams when this occurs. Generally, this sort of situation can be avoided by aiming a secondary set of front-mounted lights down at a steep angle and focused in a wide, horizontal bar shape pattern. As Kims Nissan of Laurel, a local Nissan dealer in Laurel, MS, explains: fog lights do one thing really well, they illuminate the ground immediately in front of a vehicle.

Why are they often yellow

Actually, the term used by automotive engineers is “selective yellow.” The problem is that ordinary white headlights emit a bright white light that tends to produce glare effects when it reflects of fog, rain and snow. Selective yellow light is created by filtering out the blue and violet wavelengths of light thereby reducing the tendency to produce glare. However, filtering out blue light does reduce the total light output. This is why ordinary headlights aren’t filtered to produce selective yellow light.

When to Use Fog Lights

As we explained, fog lights, unlike main beam headlights, only illuminate the ground immediately in front of your vehicle. This makes it dangerous to drive at any kind of a high rate of speed when using only your fog lights. In fact, it’s actually illegal in some areas to drive with just your fog lights on.

What are Rear Fog Lights?

While front-facing fog lamps are designed to allow you to slowly make your way through poor visibility conditions, rear fog lamps are designed to prevent anyone from hitting you from behind under those same conditions. The issue is that in poor visibility, your ordinary tail lights may not alert other drivers to your presence until it is too late.

The fact is that, while fog lights do have their uses, most people don’t actually need them. Since they are only useful in a very narrow range of circumstances, you only need them if you actually find yourself driving under those specific circumstances often. However, if you want to be prepared for bad weather conditions, consider getting a set for your car or truck.