Fog lamps were intended to help illuminate the immediate area in front of the car and the sides of the road when forward visibility is limited (e.g. heavy fog, snow and rain). Good performing fog lamps should provide a short, wide beam to help spot the edges of the road, signs, etc. with a sharp horizontal cutoff so as not to produce glare. Fog lamps were never intended to be used as "driving" lights (which have an entirely different pattern and purpose) or in most scenarios to be honest. .....only in bad weather when you are typically driving quite slow as a result.
The Outbacks have rally/driving lights (*see EDIT below) that do help in foggy or snowy situations.They are technically called rally lights everyone calls them fog lights due to the 80's marketing machine but in reality there is no such thing as a fog light especially a wide beam flood style light...
GDS I can 100% promise you there is actually nothing sold today thats an actual fog light period! The best lighting for fog or any other situation with reflective stuff in the air is a focused beam of light hence why BMW is playing with lasers to see if they can create the first ever "Fog" light.The Outbacks have rally/driving lights that do help in foggy or snowy situations.
There are vehicles that have actual fog lights, they usually have a yellowish colored lens.
Most people always use the term 'fog lights' because they don't know that there is a difference.
So, what is a good fog lamp? A good fog lamp produces a wide, bar-shaped beam of light with a sharp horizontal cutoff (dark above, bright below) at the top of the beam, and minimal upward light above the cutoff. Almost all factory-installed or dealer-optional fog lamps, and a great many aftermarket units, are essentially useless for any purpose, especially for extremely demanding poor-weather driving. Many of them are too small to produce enough light to make a difference, produce beam patterns too narrow to help, lack a sufficiently-sharp cutoff, and throw too much glare light into the eyes of other drivers, no matter how they're aimed.
Good (and legal) fog lamps may produce white or Selective Yellow light—it is the beam pattern, not the light colour, that defines a fog lamp—and most of them use tungsten-halogen bulbs though there are some legitimate (and a lot of illegitimate) LED fog lamps beginning to appear. Xenon or HID bulbs are inherently unsuitable for use in fog lamps, and blue or other-colored lights are also the wrong choice.
The fog lamps' job is to show you the edges of the road, the lane markings, and the immediate foreground. When used in combination with the headlamps, good fog lamps weight the overall beam pattern towards the foreground so that even though there may be a relatively high level of upward stray light from the headlamps causing glareback from the fog or falling rain or snow, there will be more foreground light than usual without a corresponding increase in upward stray light, giving back some of the vision you lose to precipitation.
When used without headlamps in conditions of extremely poor visibility due to snow, fog or heavy rain, good fog lamps light the foreground and the road edges only, so you can see your way safely at reduced speeds.
In some places, the law prohibits the use of fog lamps without the low beam headlamps also being on. Whether or not this is the case where you drive, it's vital to realize that fog lamp beams, by definition, have a much shorter reach than headlamp beams. If you drive in conditions foul enough to call for the use of fog lamps without headlamps, it's essential to have good fog lamps that are up to the task and are properly aimed, and it's even more imperative that you slow down because even with high-performance fog lamps, you can't see as far with fog lamps and in poor weather as you can with headlamps and in clear weather.
Here are the beam patterns of my fog lights on the road. The passenger side fog is aimed down and not very far from the front of the car. The driver side seems to be pointed out far left. Just curious if this is how everybody's fogs are.
Rayleigh's scattering law gave the misconceived notion to automobile engineers that yellow would somehow penetrate fog droplets better than white light. When that theory was later shown to be flawed, someone deemed it desirable to make fog lights yellow as a way of signalling to other drivers that visibility is poor and thus caution is in order. Yellow fog lights have more to do with tradition than science I'm afraid.subiesailor,
We are talking about accessory lighting, lighting that helps the main driving lights (headlights). I agree that standard vehicles do not have main fog lights that are supposed to be used instead of the regular main lights. Also agree that yellow does not help see through fog, but many fog lights are yellow, or they were several years back.
Thanks for the info. I don't really drive with them on, and I disable the active fogs when driving at night. When I get the oil changed, I will bring it up with subaru. If they don't fix anything I will dive deeper into it like you did in that thread.Here's a thread I started last fall that discussed the same problem: