Why are school buses universally yellow? 

All of us have indelible memories of our school lives. Don’t we? Many of these memories are created in our school buses too. You must have noticed that these buses, including your own, are all yellow in colour. Ever wondered why? Yellow is not just a signature shade. It’s a matter of safety. Read on to know more.  

The universal guideline 
For those unaware, there’s a global guideline stating that alongside flashing lights and safety devices (equipped with grilled windows, first aid boxes and fire extinguishers), school buses must also be painted yellow in colour. Before this guideline emerged (pre-1940s), the colour of school buses hovered between red, white, blue, pure orange, pure yellow (like the shade of lemon) and others, especially the first three. It was believed that those colours were most sensitive to human eyes, when in fact, it was just the reverse.  

Once the guideline was in place, school buses were given a new look, a shade that’s neither pure yellow nor pure orange, but a blend of both, almost like the colour of fresh mangoes (orangish yellow). In fact, the shade is now globally recognised as school bus yellow or school bus chrome/ glossy yellow. 

Why yellow of all colours? 
In 1939, an American educationist named Dr. Frank W. Cyr first associated the typical yellow colour of school bus with safety after a 10-day study and survey. He observed that even though the world believes red to be the most attention-grabbing colour, considering it appears in all kinds of stop signs such as traffic lights and danger or warning placards, it isn’t so. In fact, a particular shade of orangish yellow (the one you now see on school buses worldwide) gets our attention faster than any other colour. 

Here's why it happens. So, human eyes are made in such a way that even if a yellow-coloured object is not directly in front or within the close vicinity, they can catch it through the corners. This is called peripheral field or vision. Scientists, over the years, have proved that human eyes are able to detect the colour yellow by using their peripheral vision, almost 1.24 times better (thanks to its balanced wavelength and frequency that sends immediate signals to the brain) than red or any other colour. Sounds fascinating, isn’t it? Not only that, unlike red, yellow is also easily observable in a dark environment.  

So, now you can understand why school buses are globally yellow, right? Since yellow can be seen from far away (or even when it’s not straight ahead or behind), it’s the most convenient and distinguishable shade to paint on school buses.  

After all, children are a nation’s most prized possession and it’s mandatory to ensure their safety above everything else.