why are car fog lights yellow? Does it matter it their yellow?

Question

why are car fog lights yellow? Does it matter it their yellow? Does driving in the city or countryside make a difference?

Answer 1

The color used is actually called "selective yellow".

Selective yellow improves vision by removing shorter, blue wavelengths from the projected light, as bluish wavelengths are difficult for the human visual system to process properly, as well as causing dazzle effects in rain, fog and snow and might create glare.

Answer 2

Not all fog lights are yellow. Sodium lamps are yellow, but most car lamps aren't yellow. Some nicer cars have bluish-white lights from mercury.

Answer 3

Yes it matters because yellow light scatters less on fog droplets than shorter wavelenghts and we do not see well in longer wavelenght red light.