“Why are school buses yellow?”
So why do we refer to a school bus as yellow? Back in the 1930’s in the U.S., school buses were pure yellow. Thus, the term “school bus yellow” came into the English language.
Yellow (and the yellow family of colors) gets your attention faster than any other color. People notice yellow objects first.
Even when you are looking straight ahead, you can see a yellow object that is not in front of you “in the corners of your eyes” much sooner than any other color even red. Scientists describe this as follows: “Lateral peripheral vision for detecting yellows is 1.24 times greater than for red.”
Many experts also point out that colors such as yellow or greenish-yellow are more visible to the human eye under dimmer conditions compared to red.
If there’s fog or any kind of bad weather, drivers will still be able to see yellow cars and any moving vehicle fairly well.
Not only are school buses yellow, but also many earth-moving, road-building and other outdoor machines are yellow because you could get hurt if you accidentally run into one of them. Many accidents occur in farms and outdoors because the victim saw the moving object too late. If it’s yellow, you have a strong warning!
Source: Why are school buses yellow