Well I was struck by by the fact that blue is hazy and bright while yellow is better defined. If I am riding with two 55w low two 55w high 2 55w fog light (yes). Thats 330 w of bright light blinding everyone. While I could get away with that some light if yellow light.
I second fact is our eyes see yellow better as we get older due to our eye lens aging and yellowing. Think old old drivers seeing you better with yellow. Electrical engineering text suggest that older people should have yellow incandescent light to prevent headaches and eye strain. Most cheap florescent lights are blue and should be used with a yellow burning light by older that 30..
I use them, the amber color matches my Topeka Gold 06.
I ordered the H7 yellow and will try them out not so much for fog but to reduce the headlight glare from the mirrors to the lead riding partners eyes.