School Bus Stop Ahead Sign
MUTCD S3-1
A school bus stop is ahead; be prepared to stop for loading children.
What it looks like
A fluorescent yellow-green pentagon pointing up with a black legend reading SCHOOL BUS STOP AHEAD.
When you'll see it
On roads where a school bus stop lies ahead but is not easily seen in time, often just beyond a hill or curve.
What to do
Be prepared to stop for a loading school bus; slow down and watch for children boarding or leaving the bus.
Related signs
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.