As students return to school this month from a long summer off, around 30 million of them will do so on a school bus as part of the largest transportation system in the country. And not only is that school bus yellow, but it is the exact same hue of yellow that is on every school bus in the country—all 480,000 of them. Officially, it is called National School Bus Glossy Yellow and the hue was introduced in 1939 thanks to one man, Frank W. Cyr.

Cyr was born in rural Nebraska in 1900, where he earned his education, eventually obtaining his PhD at Teachers College, part of Columbia University in New York City. Cyr began teaching at Teachers College in 1930 and did so until his retirement in 1965. Because of his rural roots, he studied ways to improve rural education and transportation in America, remembering back to his own childhood and how many different ways districts transported kids to school every day.

According to his Columbia University biography: “In 1937, Cyr began a study of school transportation and found that children were riding to school in all kinds of vehicles, including trucks and buses of all different colors (one district, hoping to instill patriotism in the children, painted their buses red, white and blue). In Kansas, Cyr found one district that transported children to school in horse-drawn wheat wagons. School bus manufacturers were also complaining that, because each district could set its own standards, the manufacturers could not mass-produce buses on an assembly line.”

Something needed to change, and Cyr became the catalyst to make it happen. In 1939, with a grant from the Rockefeller Foundation, Cyr organized the first national school bus specification conference at the University of Manhattan to develop school bus standards. Delegates from all 48 state’s educational departments met with teams from many of the country’s largest school bus manufacturers at the time, Blue Bird, as well as many truck makers such as Chevrolet, Dodge, and Ford. Also in attendance were representatives from DuPont and Pittsburgh Paint companies.

The conference lasted seven days and during that time, representatives discussed and settled on 44 standards used to manufacture school buses, among them was the standardization of the color. At the conference, they hung up on the walls of the meeting room more than 50 various shades of yellow and narrowed it down to three extremely similar shades. In the end, they allowed this three-shade variation because paint (at the time) couldn’t be mixed exactly. The name of the yellow they decided on was called “National School Bus Chrome.”

The conference determined that a strong warm orangish-yellow (with black lettering) was the easiest to see in various levels of light, specifically in the morning and evening light when buses are likely to operate. According to early studies on color, the human eye notices the color yellow 1.24 times faster than the stereotypically “eye-catching” color red. As well, standardizing all buses to a single and distinct color, offered a level of psychological conditioning, making those that see this shade of yellow instantly think of a school bus.

After the conference, 35 states quickly adopted Cyr’s standardizations, including the National School Bus Chrome color scheme, while the remaining states eventually came around (the last holdout was Minnesota, which didn’t change its “Minnesota Golden Orange” to National School Bus Glossy Yellow until 1974). In 1956 the Federal government officially adopted the color as part of its Federal Standard 595 of the Federal Standard Color System (National School Bus Glossy Yellow is designated 13415 in the government’s color palette).

After World War II, many of the one-room schoolhouses disappeared as rural schools were consolidated. This led to more and more students being transported via school buses and a higher demand for student safety. Over the years, most all of conference’s 44 areas of standardization have been changed in successive rounds of safety improvements, including the chemical formula for National School Bus Chrome.

Many paints at that time were made with chromium (hence the word Chrome in the title), an element that enhanced the depth and shine of the pigment and gave it a high level of corrosion resistance. However, paints made with chromium had high concentrations of lead, and National School Bus Chrome used the worse kind of chromium known as hexavalent chromium, an atomic compound that has lost six of its electrons. With those six missing electrons, the compound will try to steal electrons from whatever is nearby, including from living cells. Chemists discovered decades later that exposure to National School Bus Chrome can damage DNA and causes cancer.

With that in mind, new lead-free paints are now used; the new formula was given a new name as well: National School Bus Glossy Yellow. The hue is the same since it was first decided upon in 1939, but the chance of inhaling hexavalent chromium from the paint has been eliminated.

Frank Cyr was eventually known as the Father of the Yellow School Bus.” He went on to become chairman of a Federal conference that set school transportation policy during World War II. In 1940, Cyr served as president of the Rural Department of the National Education Association. He is the author of over two dozen books, most concerning the education of rural America. He retired from teaching in 1965 and passed away in 1995 at an elderly care facility in Stamford, New York.

According to a biography of Frank Cyr, his son, William, once asked, “If you're the father of the yellow school bus, what does that make me?” Cyr replied that, after that, whenever the boy saw a school bus, he would say, “There goes one of my brothers.”

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Modern school buses come in most every shape and size to suit the needs of each school district. The smaller low-passenger buses are predominately based on the Chevrolet Express, Dodge Ram Van, and Ford E-Series and Transit chassis. Whereas the larger bus companies source their chassis from more heavy duty vehicle builders, such as Freightliner and Navistar (nee International Harvester). The General Motors B-Series (the GMC CV200) was replaced in 2002 by the Blue Bird Vision, while and the Ford B-Series was discontinued in 1998.

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Not only is Ryan Lee Price a freelance writer specializing in automotive journalism and a former long-time magazine editor, he is part of the technical editorial team that provides content for most all of the Chilton products. He currently resides in Corona, California, with his wife Kara and their two children.