How Fog Lights help... when there's fog?
Originally Posted by 2stroked
Actually, "fog" refers to the beam pattern - not just the color. A fog pattern light utilizes a wide, flat pattern that doesn't extend very far forward of the vehicle. The theory is that if you mount a fog beam low enough, it will shine under the fog. No need to go too far forward because the fog will disperse it. As for color, there's an urban legend that says yellow works better. Several recent studies have proven that to be incorrect. (Don't tell that to the French though.)
The other major type of beam pattern you will see is a "driving" pattern. This us generally a much narrower pattern that reaches much further down the road. As you might guess, this pattern is much better for seeing farther down the road, but pretty useless in fog. Then there's "pencil" beams, but I digress.
What comes on our trucks is actually more of a fog beam - particularly in the '04-'06 rectangular lights - not that housing shape has anything to do with pattern. Pull your truck up in front of a wall and turn your lights on. You'll see what I mean.
The other major type of beam pattern you will see is a "driving" pattern. This us generally a much narrower pattern that reaches much further down the road. As you might guess, this pattern is much better for seeing farther down the road, but pretty useless in fog. Then there's "pencil" beams, but I digress.
What comes on our trucks is actually more of a fog beam - particularly in the '04-'06 rectangular lights - not that housing shape has anything to do with pattern. Pull your truck up in front of a wall and turn your lights on. You'll see what I mean.
The best fog lights I ever had came on older Mercedes I used to own. I think they were made by Hella if I'm not mistaken. I would love to have some on my truck now for the foggy morning drives to work.
After a google search
Here are a few quotes I pulled from Google searches:
"The yellow light being of relatively long wavelength is transmitted through the colloidal size fog particles thereby permitting the driver to see, whereas the blue component of white light is scattered back to the driver thereby obscuring vision."
"Why not use red fog lights? Red light is usually a signal of danger and approaching motorists may interpret it as such. Also, the human eye is much more sensitive to yellow light than red light."
"Yellow lamps are more readily seen by an oncoming driver, so that a car with fog lights on will be seen more readily than white lights would be."
"Investigations and practices of automobile traffic do not confirm any substantial advantages of yellow light over white light. The advantages ascribed to it may take place only in very thin fog or may be subjectively received by some drivers owing to their individual peculiarities of vision. Therefore, it does not make any sense to switch over headlights to yellow light, although the use of yellow light in special fog lights does not raise any objections."
"The yellow light being of relatively long wavelength is transmitted through the colloidal size fog particles thereby permitting the driver to see, whereas the blue component of white light is scattered back to the driver thereby obscuring vision."
"Why not use red fog lights? Red light is usually a signal of danger and approaching motorists may interpret it as such. Also, the human eye is much more sensitive to yellow light than red light."
"Yellow lamps are more readily seen by an oncoming driver, so that a car with fog lights on will be seen more readily than white lights would be."
"Investigations and practices of automobile traffic do not confirm any substantial advantages of yellow light over white light. The advantages ascribed to it may take place only in very thin fog or may be subjectively received by some drivers owing to their individual peculiarities of vision. Therefore, it does not make any sense to switch over headlights to yellow light, although the use of yellow light in special fog lights does not raise any objections."
Good points. I've talked to several state DOT snowplow drivers who swear to me that yellow / amber lighting allows them to see better during snow storms. I took one of our big (private company) plows and istalled a set of Hella driving beams next to the standard headlamps. I sent our driver out with standard white bulbs in one storm and a set of amber tinted bulbs the next time. He sheepishly agreed that pattern had more to do with what he could see than color. In fact, he started running with only parking lights and the Hellas when it got ugly.
One other thing. You'll find most better aftermarket lighting companies give you a choice in fog beams. You can have amber or clear fogs. I've never seen amber driving beams offered though.
One other thing. You'll find most better aftermarket lighting companies give you a choice in fog beams. You can have amber or clear fogs. I've never seen amber driving beams offered though.
Originally Posted by Riken
these are fog lights....
https://www.f150online.com/forums/sh...ighlight=is300
https://www.f150online.com/forums/sh...ighlight=is300
Originally Posted by bud8817
they just mean you got the more expencive truck they dont help at all.... but i still want some!!!
I live in fog country where fog in extreme cases can limit driving viewing to just approx 30 feet beyond the hood with the speed of the vehicle and the rolling of the fog. Fog lights as far as I can recall, and that is many years, have always been yellow/amber in color. Fog lights are not to cut or see through fog by the carrying vehicle, but rather the yellow/amber light allows the oncoming drivers to view oncoming vehicles with a little more alertness.
The clear fog lights on current vehicles are all eye wash. A dressing. They do not help in the fog for the carrying vehicle. Fog by nature lays low to the ground and as high as the cold weather creates, especially in row crop farm country where cold weather comes in and meets the warm soil. Current day fog lights do aid in non fog weather, but for fog, in addition to headlights, they are as helpful as a 6th toe.
The clear fog lights on current vehicles are all eye wash. A dressing. They do not help in the fog for the carrying vehicle. Fog by nature lays low to the ground and as high as the cold weather creates, especially in row crop farm country where cold weather comes in and meets the warm soil. Current day fog lights do aid in non fog weather, but for fog, in addition to headlights, they are as helpful as a 6th toe.
Fog lights help alot because they are typically pretty low to the ground. They also put out a wider light pattern. I always run my fogs when my headlights are on. Of course they arent worth a damn anymore when it's foggy for me though.
Originally Posted by Req
I live in fog country where fog in extreme cases can limit driving viewing to just approx 30 feet beyond the hood with the speed of the vehicle and the rolling of the fog. Fog lights as far as I can recall, and that is many years, have always been yellow/amber in color. Fog lights are not to cut or see through fog by the carrying vehicle, but rather the yellow/amber light allows the oncoming drivers to view oncoming vehicles with a little more alertness.
The clear fog lights on current vehicles are all eye wash. A dressing. They do not help in the fog for the carrying vehicle. Fog by nature lays low to the ground and as high as the cold weather creates, especially in row crop farm country where cold weather comes in and meets the warm soil. Current day fog lights do aid in non fog weather, but for fog, in addition to headlights, they are as helpful as a 6th toe.
The clear fog lights on current vehicles are all eye wash. A dressing. They do not help in the fog for the carrying vehicle. Fog by nature lays low to the ground and as high as the cold weather creates, especially in row crop farm country where cold weather comes in and meets the warm soil. Current day fog lights do aid in non fog weather, but for fog, in addition to headlights, they are as helpful as a 6th toe.
From US DOT:
Fog lamps, driving lamps, and auxiliary low beam headlamps are lamps used in addition to the normally required headlamps. These lamps have been identified in state laws for decades as being allowed to be used under certain conditions of visibility. Generally, as defined in SAE standards, fog lamps have a wide even beam, less intense than a low beam, and intended to be mounted low to shine out under blankets of fog hovering near the ground, and in other conditions of reduced visibility such as rain, snow and dust. Properly aimed, fog lamps can be used to reduce the back scatter glare that often results from water droplets, snowflakes and dust particles illuminated by headlamps. The fog lamp with its downward aimed beam can reduce that veiling glare and permit seeing, albeit at much shorter distance, the roadway and important targets. Speeds, of course, have to be reduced under those conditions.
Do yellow fog light bulbs work better when used when the headlights are on, or does the white light from the headlights reduce visibility with yellow fog lights as much as clear fog lights?


