Asked by jim

8. Fire engines used to be red. Yellow-green is now the preferred color. Why the change?
Answered by DrBob222
The eye is more sensitive to the new color. Also, people who are color blind have trouble seeing red (and green, too, but the yellow helps make it visible.) I have noticed some blue in the green of traffic signals; presumably that is to help red/green color blind people distinguish when the green light is on.