Mom noticed a school bus on the drive home and asked Daniel if he knew why it was that specific shade of yellow.

He didn't. Neither do most people.

Before 1939, there were no rules for school transportation in the United States. None at all. Children got to school however their district could manage -- proper buses, trucks, and in at least one Kansas school district, horse-drawn wagons. The vehicles came in every color imaginable, which meant other drivers on the road had no way of knowing which ones were carrying children. No reason to slow down. No reason to be careful.

A professor at Columbia University named Frank Cyr decided to change that. He spent two years traveling the country studying how children got to school. Then in 1939 he organized a national conference in New York -- transportation officials from every state, en ...