Per 49 CFR 383.5, a commercial motor vehicle qualifies as a "school bus" for CDL purposes when it is used to transport students in which of the following ways?

49 CFR 383.5 (definition of "School bus")

Whether a vehicle legally counts as a "school bus" determines whether the S endorsement is even required, so understanding the precise boundaries of the definition (including the for-hire carve-out) matters for both test-takers and employers classifying their fleet correctly.