>>283438the yellow lights are more efficient for the eye to see than the blues and violets - they were put on cars not quite so much for the benefit of the driver but for the benefit of oncoming traffic/pedestrians/etc. it's not as obnoxious to be looking at a yellow light because it's very easy on the eyes.
low pressure sodium street lamps are also yellow, and partly the justification is the reduced glare/dazzle/disability of yellow but mostly in that case it's because they're so god damned efficient and happen to be yellow too
why blue is said to be better for fog is probably because the short wavelengths of blue will actually reflect and scatter off the fog thus making it more visible. so the blue probably isn't so much for seeing through haze/vapors but for detecting them