Originally posted by TheContourGuy:
It has been shown that the dichroic yellow bulbs do not work any better than a standard 'white' bulb in cutting through fog, so I'd say if you think it looks cool then go for it. But don't spend extra money on them because they work better.
Bzzzt, wrong answer!
posted from
here Selective-yellow light can improve fog lamp performance, because it is lacking in the high frequency/short wavelength blue light that reflects readily off atmospheric moisture (frozen or not) and into your eyes. 
