The yellow school bus has kept its special color for many years.

In 1939, transportation officials from all 48 states chose this color.

They picked it because it is easy to see.

This made it one of the first safety rules.

In the 1980s, the bus was most popular.

At that time, it carried more than 60% of U.S. students.

The bus started in rural America.

A car dealer named Albert Luce, from Georgia, designed it for cement workers.

Later, he sold it to schools when his company did not grow.

This happened at the same time that districts replaced small local schools with bigger, faraway ones.

Matt Anderson is a curator at the Henry Ford Museum.

He says these two changes depended on each other.

Later, buses helped with desegregation.

They moved Black and white children across racial lines.

That practice has mostly ended now.

Schools have become more separated again.

Carl Fisher drove a school bus for 66 years.

He retired in 2012 as the longest-working driver.

His first bus was a changed Dodge truck.

It carried 20 children.

Safety upgrades have included padded seats and a flip-out stop sign.

Brad Beauchamp works for Blue Bird, the bus maker.

He calls it the safest road transport per passenger without seat belts.

Now, a shortage of drivers means many students do not get bus service.

Jim Oppegard retired at 94 as the oldest driver.

He said the work was rewarding and important for society.