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Do fog lights really work, or just look cool?

The good ones are amazing. The bad ones are a joke.

Brian Cooley Editor at Large
Brian Cooley is CNET's Editor at large and has been with the brand since 1995. He currently focuses on electrification of vehicles but also follows the big trends in smart home, digital healthcare, 5G, the future of food, and augmented & virtual realities. Cooley is a sought after presenter by brands and their agencies when they want to understand how consumers react to new technologies. He has been a regular featured speaker at CES, Cannes Lions, Advertising Week and The PHM HealthFront™. He was born and raised in Silicon Valley when Apple's campus was mostly apricots.
Expertise Automotive technology, smart home, digital health. Credentials
  • 5G Technician, ETA International
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Brian Cooley
2 min read
Subaru

Real fog lights sneak light under fog and mist instead of bouncing back it back into your eyes, yet a number of people have emailed me who are skeptical of that.

A well-designed and -placed fog light sits lower than a headlight is legally allowed to. It will have a flatter beam that doesn't rise up as much as headlights and will have a wider beam to cover as much of the road width as possible.

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Fog lights have the shortest, widest and lowest beam of all automotive lights meant to illuminate the road.

 PIAA

If they accomplish all those things, they give you better lighting in dense conditions, but still not the full depth of vision you have from headlights in clear weather. The rules of physics make it tough to pass photons through water droplets without some coming back. Never outdrive whatever forward lighting your car has.

Watch this: Are the fog lights on your car really worth it?

Fog lights are common on upper trim levels of many cars or, if you bought a low trim level, easily added via a set of OEM-style fog light modules that drop into the molded well on your front lower bumper of fascia. Trickier will be the potential absence of a factory wiring harness to power and control add-on fogs, but running those circuits yourself isn't very hard with a good relay kit.

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A nicely integrated factory fog light need not be rectangular to throw the desired wide, flat beam. It's all in the lens and reflector design.

 Mopar

With similar effort you can add aftermarket fog lights that have a certain retro rally charm about them: Marchal, Cibie and Carello are some of the classic fog light brands that are easy to find new or used in the iconic rectangular shape. 

If you envy the vintage Euro/American mashup look of the 1965 Mustang in A Man and a Woman, know that its distinctive yellow fogs were big in France and other francophone countries thanks to a belief that their wavelength reflected less glare. That has not only been debunked, but yellow forward-facing lights have been illegal in France since the early '90s and may run afoul of your state's vehicle codes here in the US. Not that they aren't available and don't look cool.