If someone asks you to think of a school bus, you can only imagine it in yellow. Since 1939, school buses have been painted yellow and there’s a good reason behind it. Back in 1939, Frank W. Cyr, “father of the yellow school bus,” held a conference for transportation officials, educators, school bus manufacturers and, paint experts. Cyr did extensive research on his own and learned that there were no standards for the color of school transportation. After a seven day conference, the attendees came to the conclusion that yellow be standardized as the national color of school buses. The roof’s were not painted white until decades later but yellow became the standard color for school buses.
Even during poorest of weather conditions, yellow is the safest color for moving vehicles.
According to research, lateral peripheral vision for detecting yellows is 1.24 times greater than for red. So, in short, people are more likely to recognize the color yellow than any other color and the reason the color was associated with the safety of the young ones. According to the National Highway Traffic Safety Administration, “all school buses should … be painted National School Bus Glossy Yellow, in accordance with the colorimetric specification of National Institute of Standards and Technology (NIST) Federal Standard No. 595a, Color 13432.”
But why do some school buses have white roof tops?
According to a 1992 New York Times article, recently referenced by Accuweather, a school bus roof color can have a big impact on the temperature inside. According to the New York Times archives, white-topped school buses were first used in California around 50 years ago. Over time, other states started using them to help conserve energy as well as to make the inside of the school buses a bit more comfortable.
In 1992, a study took place in North Carolina to determine the relationship between roof color and inside temperatures. As part of the study, thermometers were planted inside the buses and readings were taken four times per day from August to December. Researchers conducted the test while the buses were running and while they were parked.
The study discovered that buses that had white tops had significantly lower temperatures inside than others. Buses with white tops dropped interior temperatures an average of 10 degrees Fahrenheit during the summer, with as much as a 17-degree difference at peak hours. During cold weather, the temperature only differed by 3 to 4 degrees. Bus drivers also reported seeing behavioral improvements as a result of the temperature drop.
Separately the study also found that these two-toned buses were reported to be easier to see by other motorists. As a result of the program, North Carolina school systems were given the option to specify white tops when ordering buses. Although it cost an extra few hundred dollars to paint the roof white, it’s much more comfortable and safer for its occupants. Today, it’s not just school districts that utilize the white top roofs but UPS also paints their trucks’ roofs white to cut down on cooling costs inside the vehicle.