> Contrast with highways where you do want people to stay awake, so blue makes sense
I remember some kind of study around yellow light being ideal for roads actually. The human eye is more sensitive in the green/yellow part of the spectrum, the lights are more efficient and cut through fog better.
The difference between white & yellow light in fog is minimal. What really makes fog lights effective is being under 18 inches off the ground so they shine under the fog.
White light scatters more since it contains multiple wavelengths, generating more glare and losing brightness faster. And this is about street lighting, a 10% difference in brightness can result in massive energy savings.
