There's A Very Good Reason Why American School Buses Are Painted Yellow

For nearly a century, one color has ruled America’s roads every school morning: that unmistakable glossy yellow. It’s not by chance – it’s all thanks to one determined educator called Frank W. Cyr.

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Cyr, a professor at Columbia University who passed away in 1995, became known as the “father of the yellow school bus” because of his work in the 1930s that set many of the modern school bus standards.

In 1937, Cyr began a study of school transportation across the US and found that children from different states were traveling to school in all kinds of vehicles. They came in all shapes, sizes, and colors. One district painted its buses red, white, and blue to season the children with some all-American patriotism. Another district in Kansas even transported children to school in wooden, horse-drawn wheat wagons.

Aside from being chaotic, the situation was potentially dangerous and in need of firm regulation.

So, in 1939, Cyr organized a conference that oversaw the creation of 44 standards for school buses, including body length, ceiling height, and aisle width. It also mandated that school buses should be painted with a particular yellow-colored paint.

It was chosen for a simple reason: yellow has a high luminance value and a strong visually perceived brightness. In other words, the color really "pops". 

Human eyes are especially sensitive to the yellow wavelength of light, and it’s brilliant at attracting attention. It also remains vibrant in lower light conditions, such as during dusk and dawn, when kids are coming to and from school. It's a similar reason why high-visibility clothing and marker pens tend to come in yellow. 

Additionally, making the color uniform across the country reinforces the association in people’s minds, helping them recognize yellow buses as a signal to take caution because careless children are likely nearby.

“They wanted a color that would stand out, that other drivers could see from a distance and that would be identified with a school bus, so whenever we saw it, we’d think, there’s a group of kids going someplace,” Frank Cyr’s son, William, told the New York Times in 2013. “Before that, they sent kids to school in anything.”

The color chosen at Cyr’s conference was called "National School Bus Chrome,” although it’s also known as “National School Bus Glossy Yellow.” Most of the other regulations set out by the meeting have changed over the past eight decades, but this iconic yellow paint has stood the test of time.