India, Aug. 29 -- In today's episode of Everyday Explained, we're looking at something you've probably seen countless times but may never have questioned: the bright yellow school bus. From the United States to parts of Canada, the colour has become closely associated with school transportation. But why yellow? The answer has less to do with aesthetics and more to do with visibility, safety and a decision made nearly a century ago. (Also read: Everyday explained: Why are keyboard letters not arranged in alphabetical order? )

The yellow colour used on American school buses can be traced back to a 1939 conference at Teachers College, Columbia University. According to the National Highway Traffic Safety Administration (NHTSA), education off...