Is it true that yellow fog lights work better than clear (white) fog lights in the fog?
I don’t know, although I have been told this many times over the years. I am not an automotive lighting engineer. However, a former lighting engineer from Mercedes AG told me that this is true, that yellow bulbs work better because yellow light reflects less off of fog. A month later, a current automotive lighting engineer at General Motors also concurred with this opinion. Here is another fact that they both added to their answer – a yellow bulb inside a clear lens is much more efficient from a lighting perspective than a clear bulb inside a coated yellow lens. They both said that coated lenses produce a 30-50% decrease in light output, depending on how thick the coating on the lens was applied. The ex-Mercedes engineer noted that before the mid-70’s, manufacturers generally used coated lenses for yellow fog lights (as did Mercedes), but as soon as the bulb technology improved everyone went to yellow bulbs housed in clear lens modules. It should be noted, however, that there are many
