The familiar sight of a school bus is synonymous with childhood memories and daily routines. But have you ever stopped to wonder why the tops of these trusty vehicles are always painted a brilliant white? It’s a design element so ubiquitous that it’s easily overlooked. Yet, it serves a critical purpose that goes beyond mere aesthetics.
Let’s take a closer look at the fascinating reason behind this distinctive feature. And uncover the safety-driven ingenuity that’s been hiding in plain sight.
A School Bus
A school bus is any type of bus owned, leased, contracted to, or operated by a school or school district. It is regularly used to transport students to and from school or school-related activities, but not including a charter bus or transit bus.
Various configurations of school buses are used worldwide; the most iconic examples are the yellow school buses of the United States which are also found in other parts of the world.
In North America, school buses are purpose-built vehicles distinguished from other types of buses by design characteristics mandated by federal and state/provincial regulations.
In addition to their distinct paint color (National School Bus Glossy Yellow), school buses are fitted with exterior warning lights (to give them traffic priority) and multiple safety devices.
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, and school bus manufacturers. And learned that there were no standards for the color of school transportation.
After a seven-day conference, the attendees concluded that yellow be standardized as the national color of school buses. The roofs were not painted white until decades later but yellow became the standard color for school buses.
Yellow is the safest color for moving vehicles even in the poorest weather conditions
According to research, Lateral Peripheral vision for detecting yellows is 1.24 times greater than for red. So, people are most 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, following the colorimetric specification of National Institute of Standards and Technology (NIST) Federal Standard No.595a, color 13432.”
But why do some buses have white rooftops?
According to a 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 steps 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 California to determine the relationship between the 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 3-4 degrees.
But drivers also reported seeing behavioral improvements as a result of the temperature drop.
The study’s findings are in line with research at Berkeley Lab’s Environmental Energy Technologies Division published in 2011. That study found that white, silver, and other light-colored cars are the coolest, reflecting about 60% of sunlight.
Interestingly, some dark “cool colors” that reflect primarily in the “near-infrared” part of the solar spectrum, can also stay cooler than darker cars, according to the study.
Summary
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 costs an extra few hundred dollars to paint the roof white, it’s much more safer for its occupants. Today, it’s not just school districts that utilize the white top roofs but UPS also paints their truck’s roofs white to cut down on cooling costs inside the vehicle.
