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View Full Version : here comes a can-o-worms: yellow fog lights



trfourtune
07-30-2009, 04:51 PM
Well, I'm going to open up the old can of worms here after doing a lot of research: why are/were fog lights yellow.

First there are a lot of "scientists" on the net stating that they don't do anything(yellow that is). Making all sorts of statements about scattered light etc.

It has NOTHING TO DO WITH THAT.

Adding yellow/orange filter to lights WILL reduce the light intensity available unless you increase the light source so that is not the point.
The whole matter is based on human anatomy of our eyes and brains. What the yellow does do is help our eyes and brains perceive less GLARE. When your eyes perceive glare, it makes it harder to see. It's like overload to the brain.
I personally do drive in snow and fog and i do find that yellow helps with my ability to see in those conditions.

Remember that when it is really foggy or snowing very, very hard, you are not looking for long range vision, you just want to see the road.

the bait is cast!
anyone?
Rob

tomshobby
07-30-2009, 05:01 PM
Probably for the same reason competition rifle shooters wear yellow shooting glasses.

trfourtune
07-30-2009, 05:06 PM
I think shooting glasses are yellow for a different reason, but has to do with your eyes as well, wich i think is a contrast perception, like the effect on photography in black and white. Makes a big difference.

TR3driver
07-30-2009, 06:59 PM
Must depend on your eyes ... I find that yellow fog lights do nothing for me; while yellow "shooting" glasses do help (but not as much as good Polaroid lenses). Probably depends on the fog, too, I haven't driven in more than very light fog for many years; but I have driven in fog so dense that I had to open the door and look down to see the lines on the road.

My _guess_ is that yellow fog lights work more like the red lights used on ship's instruments; they spoil less of your night vision than white lights do. Red would be even better, but of course it is illegal to show red to the front, so yellow is a compromise.

TOC
07-30-2009, 07:27 PM
I've still got several sets of yeller fog lights.
Couple of pair are six volts.
I remember driving north of Bakersfield when you couldn't see squat, and Slaughter Alley.

The lack of glare-back certainly seemed to help.
If you want to prove it to yourself, try hitting your high beams next time you hit a fog bank.
I have never seen actual "banks" like in Southern California.
Holy Bat-Poop.

That said, my Lucas FogRangers aren't yellow at all.
Haven't really seen them to be as efective as the old yeller ones, either.

Dave

MrT
07-30-2009, 08:00 PM
I had yellow fog lights on my spit in the 80's , I got pulled over by a cop comming the other way. He said he was totaly blinded by the fog lights . he gave me a warning . at the time I had KC highlights 55 watts . not a big deal and not so bright by todays standards. this event happened in NJ . I now live in FL and see lots of very bright aftermarket headlights on cars. The fog lights worked great in the fog / rain / and snow. I used then all the time and they do work.

Mr.T

aeronca65t
07-30-2009, 08:18 PM
If you really, really, really are interested in this topic, there's an SAE research paper on it ~HERE~ (https://www.lightingresearch.org/programs/transportation/pdf/SAE/2001-01-0320.pdf)

Long story short is that the study concludes it doesn't really make much difference. :smile:

Brosky
07-30-2009, 08:20 PM
The key to fog lights is in the mounting. You want them down low, under the fog. Up high and they are just another headlamp.

Tinster
07-30-2009, 08:24 PM
Probably for the same reason competition rifle shooters wear yellow shooting glasses.

Many sport fishermen also wear yellow, polarized glasses for the same reason:
Glare and boater's fatigue syndrome.

dale (Tinster)

edit-sticky keyboard key.

Roger
07-30-2009, 10:19 PM
I was living in France in 1994 when yellow headlights were phased out. Until then, they had been mandatory.
And there really did seem to be less glare! Oddly, although you could keep your yellow lights if you wanted, many, many people changed and by early '96, when we left France, there were few yellows left, around the Paris area at any rate.

TR3driver
07-31-2009, 12:32 AM
If you really, really, really are interested in this topic, there's an SAE research paper on it ~HERE~ (https://www.lightingresearch.org/programs/transportation/pdf/SAE/2001-01-0320.pdf) I didn't wade through the whole thing, but it seems to me there are some problems with their statements. For example, they dismiss Rayleigh scattering because snow and rain particles are too large; yet we were only talking about fog particles. A US Army paper I found here
https://ams.allenpress.com/perlserv/?requ...CO%3B2&ct=1 (https://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0469(1978)035%3C2020:VSIAFA%3E2.0.CO%3B2&ct=1)
talks about a peak in fog particle size between 300 and 600 nm; exactly the range subject to Rayleigh scattering.

It also seems to me that they are assuming that the luminance of the objects of interest is constant, rather than being governed by how much of the light from the headlights reaches the objects. That tends to negate the argument about light being lost in the yellow filter, because the driver's eyes can then adjust to the lower light levels. If we could see the road without the headlights, we would just turn them off! (And I have driven in fog where it was easier to see that way.)

kodanja
07-31-2009, 09:21 AM
I had these yellow Lucas lenses on my car for a short while, till I looked at it and realized how GAY they looked'

https://i90.photobucket.com/albums/k270/KODANJA7/DSC05840.jpg

trfourtune
07-31-2009, 09:46 AM
Kodanja, i agree, that's because you have the colours backwards, LOL, you're going at it the wrong way. Randall is right about the colour red-it is supposed to be better but not allowed. I don't like my regular driving lights to be yellow, just fog.
Now, i guess i should start a thread on BLUE lights and why they should be banned from the street, IMHO (fine off road where on comming traffic doesn't matter). The dreaded glare. It's great to see ahead better but if you glare the oncomming traffic so bad they can't see because of your lights and they swerve and have a head with you-guess what-you and your blue lights are the problem, not them. Save your spot lights for off road.
Rob

kodanja
07-31-2009, 10:05 AM
aint it the truth bout the blue lights~!!!

Im much happier with a classic look~!
https://i90.photobucket.com/albums/k270/KODANJA7/tr64-5-910.jpg

tomgt6
07-31-2009, 11:18 AM
Well, coming from a motorcycle point of view I want to be seen and want to stand out. I put a 6000 color HID on the motorcycle. It has a blue tint but isn't as blue as most. But I can say I can be seen by more people and they stand out verses the 4300 color of most head lights. If the headlights are pointed correctly this should never be an issue.

JamesWilson
07-31-2009, 12:55 PM
I was living in France in 1994 when yellow headlights were phased out. Until then, they had been mandatory.
And there really did seem to be less glare! .... there were few yellows left, around the Paris area at any rate.

:iagree:

I'll second this opinion. I too thought that the yellow tint made driving easier on the eyes with less glare generally. Of course being on the wrong side of the car on the wrong side of the road might have had an effect on that perception....

Geo Hahn
07-31-2009, 05:31 PM
I had these yellow Lucas lenses on my car for a short while, till I looked at it and realized how GAY they looked

Not that there's anything wrong with that.

DaveatMoon
07-31-2009, 09:39 PM
You have to remember that lighting the road in the fog is at best a secondary consideration for fog lights. Their real purpose is for <span style="text-decoration: underline">others</span> to see <span style="text-decoration: underline">you</span>. As such yellow tint helps to make the light stand out more, and look less like a reflection or a more commonplace light source (street light, etc.).

<span style="text-decoration: underline">Driving lights</span> are used to light the road in front of the car, hopefully in a legal manner. Fog lights <span style="text-decoration: underline">should</span> be designed with a wider/broader scattering of light via the reflector and lens for maximum visibility. If you find both types mady by the same manufacturer (<span style="font-style: italic">often they look identical and you have to read the packaging to to tell them apart</span>) and compare their projection patterns, you'll find the driving lights to be more focused and the fog lights spreading illumination as wide as possible.

Rear fog lights, seen on many Volvos and Hyundai SUVs, are bright red for the same reason front fog lights are yellow. They're very handy when somone comes up on you from the rear in the fog. They're easy to mistake for brakes lights if someone's dumb enough to run them under clear conditions, however.

Roger
07-31-2009, 10:03 PM
I was living in France in 1994 when yellow headlights were phased out. Until then, they had been mandatory.
And there really did seem to be less glare! .... there were few yellows left, around the Paris area at any rate.

:iagree:

I'll second this opinion. I too thought that the yellow tint made driving easier on the eyes with less glare generally. Of course being on the wrong side of the car on the wrong side of the road might have had an effect on that perception....

Well, maybe, but I had at that time a car for the purpose - a left-hand drive VW Polo GT G40 - one of my all-time favourites.

kodanja
08-02-2009, 10:41 AM
I had these yellow Lucas lenses on my car for a short while, till I looked at it and realized how GAY they looked

Not that there's anything wrong with that.

that closet door opening for ya? :banana: