History of school bus stop arm
A tray with the word "STOP" painted on.
1946-2004EditVacuum (air) stop arm with a red octagon stop sign on it.
1994-PresentEditElectric stop arm standard lights or no lights . in the 1980s this was started used for ice cream trucks too.
A caution Plate instead of a stop sign wasn't used in 1991 and 2000. But still exists on Some older school buses or ice cream trucks