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Why are school buses yellow?

It's not federal law, but it's common knowledge. School buses are yellow. Why? The color choice is actually supported by science.

LOUISVILLE, Ky. — Another summer has come to an end and, to the horror of kids across the country, it’s time to head back to school. As kids get ready to hop on their buses and kick off the 2019 school year, there may be something you’ve never questioned – so we’ll do it for you!

Why are school buses yellow?

Whether you're getting on a bus in Kentucky, or Indiana, or Colorado, or New York, it's going to be yellow. However, there's actually no federal law requiring all school buses to be yellow. So, why don’t we see purple or green buses?

While there isn't a law, there is a recommendation from the National Highway Traffic Safety Administration that all buses be painted what they call "National School Bus Glossy Yellow."

Credit: Getty Images/iStockphoto
A row of yellow school buses parked at a lot against colorful autumn trees

It's been this way for decades. All the way back in 1939, a conference was convened by an education specialist named Frank Cyr. He was the man who worked on many of the transportation standards for schools that are in place today. His commission recommended the color choice.

Here's the reason behind yellow:

Our eyes see different colors because they have different wavelengths of light. Picture a rainbow: Red has the longest wavelength, and violet has the shortest. Right in the middle are yellow and green, making them the most visible and noticeable colors.

In darkness, rain, or fog, this yellow helps other drivers spot buses on the road. Plus, the black letters on them are easier to read because of the contrast.

RELATED: How to get your kids back on a school-friendly sleep schedule

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Want to know "WHAS up" with something? Rob Harris is your guy. He's talking to some of the smartest people in our community to find out more about science, history, urban legends, local quirks, and more.

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