The school bus stop arm:
Correct. The stop arm signals approaching traffic to stop. Drivers who pass a stopped school bus with red lights flashing face heavy fines.
CDL Practice Question #467
Category: School Bus
Why this question matters
This question is one of 55 in our School Bus bank. The reasoning above comes directly from the AAMVA CDL Manual, the source document used by every U.S. state DMV. Memorizing the underlying rule — not just the letter answer — is what separates passing on the first attempt from a return trip and another fee.