Why School Buses Are Yellow

Smithsonian Magazine tells us that it's not mandatory, but is by design:

In a 1939 issue of American Childhood, the lyrics to the song, “The Wheels on the Bus,” made their first public appearance. Songwriter Verna Hills composed verses that celebrated the routine of traveling on a bus, closing each with the phrase, “over the city streets.” Likely unbeknownst to her, at that same time 80 years ago, school transportation officials from each and every state gathered in New York to decide what that bus, with its wheels going “’round and ’round” and its horn going “beep beep beep,” would look like.

The brainchild of education expert Frank Cyr, the meeting at Columbia University carried the goal of establishing national construction standards for the American school bus. Two years earlier, Cyr had conducted a ten-state study where he found that children were riding to school in trucks and buses of all different colors, and even horse-drawn wagons, in the case of one Kansas school district he visited. Standardization would solve two problems and simultaneously revolutionize school buses themselves: one, being uniformly one color would make bus travel safer; two, costs to districts would be lower as construction specifications would make it possible for manufacturers to mass-produce buses...

During those seven days of deliberation in the Grace Dodge Room at Columbia Teachers College, Cyr said he hung strips of different paint colors from the wall, in “50 shades ranging from lemon yellow to deep orange-red.” The conference attendees, which included representatives of the bus manufacturing industry, selected a small group to make the final color selection, and the orangish-yellow color they chose has been the industry standard ever since. Initially christened National School Bus Chrome (a reference to the lead-chromate yellow in the original paint), the United States General Services Administration (GSA) now calls the color National School Bus Glossy Yellow, or Color 13432 in the Federal Standard 595a color collection that GSA uses for government procurement. The National Highway Traffic and Safety Administration (NHTSA), the federal agency that regulates bus safety, states on its website that federal law does not require school buses to be yellow, as “State and local governments establish policy for student transportation, including how buses should be identified.” Instead, NHTSA encourages states to adopt its voluntary guidelines on operational safety, like Guideline 17, which “recommends that school buses be painted ‘National School Bus Glossy Yellow.’”

Who knew?!