I have asked this question on other boards without a satisfactory answer. I have also researched the issue and found no reply to my querry, to wit; Why are some european cars outfitted with yellow lamps? Don't get me wrong, I have no problem with them, in fact I love them, I'm just curious. Its interesting also that the W123 Benz has the yellow fog lights on the american version but integrated clear lenses and lights on the Euro version-a case of complying with US Fed law as I understand it. So, I figure there is probably a similar Euro regulation to explain it. Is there, does someone know what it is? I'm just curious about it, what do you all know?
I never tried to confirm it via research, but I always thought that yellow light gives better visibility in fog since it has less reflection/glare off the fog moisture particles.
I also noticed that when I wear glasses with yellow lenses, and then I look at something yellow like the lines along a highway, the lines look pink until my eyes readjust. But this has nothing to do with the yellow lights, I only added it to make conversation.
Yellow helps give contrast when everything is white. I used yellow fog lights when living in Alaska. When the ground is all white it's hard to see unlevel ground, such as a pile of snow. You find it when you run into it. Yellow lights will cause a shadow around it and the pile of snow is visable. It works similiar in fog. It doesn't help you see farther, just gives conrast to what you can see causing irregularaties to stand out. Amber (yellow) lens glasses does almost the same thing in a different way. Something about color, absorbtion and reflective ability.
To me, yellow lights are fog lights and white lights are driving lights. Not sure why on the american-spec vs Euro-spec cars, I'm sure there's some regulation on it though.
You might like the link, it's a detailed research project on the history of headlights in the world.
From page 14 of the report:
In 1937 France legislated that headlamps emit (selective) yellow light (Jehu, 1954; Nelson,
1954). The French gave the following reasons for requiring yellow light: improvements in visibility
under conditions of glare, and, even more important, reductions in fatigue under glare conditions. The
yellow headlamp color was obtained by several different methods: a glass bulb with a different
chemical composition, coatings on the glass bulb, a yellow headlamp lens, or a yellow filter. Because
the yellow glass for bulbs reduced the emitted light intensity by about 18% (Jehu, 1954), this may
have contributed to the perception of reduced glare from yellow headlamps. Many tests were run in
different countries which failed to show any significant advantage in favor of yellow headlamps
(Schreuder, 1976). However, within France, the mandatory use of yellow headlamps continued until
the early 1990s.
and since the software doesn't seem to include the link (Christ is this software clunky!), here's the address:
http://deepblue.lib.umich.edu/bitstream/2027.42/49367/1/UMTRI-98-21.pdf
Now that was the answer I was looking for! Thanks for the awesome response. I like the ambers and have big fogs on my BGT. I thought about putting amber "appliques" on the headlights but figured it would be overkill and its actually illegal in my state. Anyway, thanks!
