How school buses became yellow, and some of the safest vehicles on the road

In the early days of busing kids to school, buses were painted all sorts of colors, and built to different specs. But in the late 1930s, education expert Frank Cyr started agitating for a national standard — so manufacturers could mass-produce to one spec, making buses cheaper.

In 1939, Cyr met for one week with school-transportation officials from across the country, and they hammered out a spec. One key decision? Setting the official color of school buses. They hung "hung strips of different paint colors from the wall, in '50 shades ranging from lemon yellow to deep orange-red'", as Smithsonian writes — and the winner was an orangish-yellow.

Why that color? Because it's easy to see, making buses readily identifiable on the road, very useful for safety. What's more, the particular shade of yellow they picked has some cool spectral qualities that make our perceptual apparatuses jump to attention, notes Ivan Schwab, clinical spokesperson at the American Academy of Ophthalmology:

The wavelength of the popular school-bus color is "right smack in the middle" of the peak wavelengths that stimulate the photoreceptor cells our eyes use to perceive red and green. The red and green photoreceptor cells, or "cones" as they are commonly known, are the two most predominant cones in our eyes. Schwab says, "If you get a pure wavelength of one color…and you hit just one cone with it, you're going to have x amount of transmission of signal to the brain. But if that [wavelength] were to stimulate two cones, you'll get double the amount of transmission to the brain." Remarkably, "That color that we are calling school bus yellow hits both peaks equally." So although they may not have fully comprehended the science behind it, the color Cyr and his colleagues chose at the 1939 conference makes it hard for other drivers to miss a school bus, even in their peripheral vision. "And it's darned big," Schwab adds.

The committee was obsessive about safety in all ways — and they argued for days about "body lengths, ceiling heights, door specifications, and aisle widths." As it turns out, their deliberations were lifesaving, because the tradition of safety-consciousness they set carried on for decades. The standards for school buses have been revised a bunch of times, as new safety tech has emerged, and the upshot is buses are 70 times safer to travel in than cars; the National Highway Traffic Safety Administration calls yellow buses "the safest vehicle on the road."

Given today's right-wing denigration of governmental expertise, it's worth pondering the value of careful, smart work by folks with deep expertise trying to serve the public.

(CC-2.0-licensed photo of a school bus courtesy Steven Mileham's Flickr stream)