Bad weather is always around the corner. You got off work on a cold winter evening, and not only is your mind foggy, but the weather too. Visibility under zero is prone to create dangerous conditions on the road, even for experienced drivers. According to FHWA Road Weather Management, more than 38,700 vehicle crashes are directly connected to poor visibility, especially fog. Needless to say, although the weather cannot be controlled, drivers do have multiple options available on the market to prevent the temporary impairment caused by low visibility conditions.

Why are drivers affected by fog?

After all, human vision is all about light – after being reflected off an object, it hits the retina, resulting in the perception of colors and white light, or, more specifically, the objects near us or far away. In case light cannot be adequately reflected, it also cannot be converted into electrochemical signals, which means that we can’t confidently see or process what is before our eyes.

There are at least two ways of explaining such a phenomenon. The tiny droplets of fog tend to scatter or disperse light either in all directions or bounce the light from particles back to the initial direction. Due to such interaction between light and dense and fine particles, the scattered light may appear white because of the ice crystals in the fog that act as prisms and cause light to split into colors.

Moreover, when dense and fine particles scatter light, like in the case of high clouds and fog, it becomes impossible to visually separate individual cloud droplets from one another. Thus, humans can perceive the area covered by fog as a single homogeneous collection of water droplets. If something obturates our sight, then the perception of objects (and visual sensation) is impaired, enhancing the risks drivers are exposed to when they’re on the road.

Therefore, our vision is put to the test when we encounter a dense fog. The world seems like a blank canvas that appears white from all directions. This can be an uncomfortable scenario for any type of traveler. But don’t be afraid of the fog anymore; it is yet to harm you in any way as long as you keep your distance from it… or you get yourself some fog lights.

So… what are fog lights?

Fog lights—like most other safety features—are highly functional, yet you might not know how much of a difference they make until you don’t have them. And then you don’t want to live without them. 

What are they, and what do they do? What you see is what you get: fog lights are a type of small automotive light designed to transmit light in a bar-shaped beam, designed to be much wider than high beams, allowing it to spread out below the fog and shine where other headlights cannot reach. In a nutshell, fog lights are … lights for fog (but not only).

Since most fog is relatively shallow (only a few inches deep), the light from fog lamps reaches the ground without scattering. The sharp cutoff prevents the reflection of light off of water droplets and eliminates glare for oncoming vehicles. Fog lights may also contain a horizontal slash of light to illuminate signs or reflectors placed down low before the curve of the road, eliminating some blind spots caused by fog, rain, or snow.

The name “fog light” is somewhat of a misnomer because it can be used during any type of inclement driving conditions. Now, what does that actually mean? In practice, this type of auxiliary light comes in handy when visibility drops below 100 meters, but the legal requirements around their usage may depend on the state.

More specifically, such subpar weather conditions include:

  • Rain;
  • Snow;
  • Dust;
  • Sandstorms;
  • Mist;
  • Fog;
  • Smoke.

Having a calculated placement and complementing headlights, they are mounted as low as possible, typically below the headlight assembly, in the lower bumper cover, not less than 12 inches nor more than 30 inches above the level surface upon which the vehicle stands, as the California law states.

When should you use fog lights?

The legal definition of when a fog light is required differs by location, but what isn’t legally ambiguous are the advantages of having two fog lights installed on your car for cases in which when visibility drops below 328 feet (100 meters). The driving benefits include better clearance, improved side visibility, and more light to illuminate your driveway or front porch.

If your headlights aren’t enough for you to see through the fog, if you can’t see the road markings, if you can’t see the road signs…well, then it’s probably time to turn on those nifty fogs. Think of it this way: when visibility is so poor that you’re imagining a dog driving down the road and waving at all of his friends, that’s probably a good time to hit the switch.

Bear in mind that each jurisdiction has different requirements when it comes to fog lights. For example, in Florida, it is illegal to use fog lamps (or any other type of auxiliary lights) when other vehicles are on the road unless the weather conditions qualify as “poor visibility.”

When should you definitely NOT use fog lights?

Since now we are aware of the legal consensus revolving around fog lights usage, let’s go over some other situations where having fog lights may come in handy, but you should beyond any doubt resist the urge to try them out:

  • You see something cool (or THAT ex) in the distance and want to get a better look (or you get struck by those repressed emotions and want to blind them through a sudden visual numbness);
  • When you’re tired of the good modern follow-heart online dating strategy, and you want to bring out that flashy & sassy attitude;
  • You want to purposely intimidate other drivers on the road and give them something to talk about later;
  • The police are chasing after you and your friends who have some very incriminating evidence that they can’t take back now that they’ve taken it from the crime scene (and planted it at another crime scene).

No. Just don’t. It’s most likely illegal.

Are there different kinds of fog lights?

While the original fog lights were primarily circular, there are now a variety of shapes and styles that you can buy, from square or rectangular lamps to those that fit behind your grille. Fog lights can also be either high or low-beam depending on what you need for your vehicle – low beams projects light further and give you a wider view of the road, while high beams allow you to see better as they shine farther than normal.

The light emitted by fog lights is generally amber / yellow as the human eye tends to be more tolerant to warmer colors (2000-3000 kelvins), but they can be white as well. Regardless of the color you choose, both reduce glare and light bouncing, although the yellow fog lights may perform better due to their shorter wavelength.

In conclusion, the weather may be foggy, but your vision and automotive lighting purchases don’t have to be. Light up the fog and shine your way, safely, through to your destination. Choosing one of the best fog lights from our recommendations will ensure you won’t ever be taken by surprise by any puddle, pothole or obstacle in your way: