How does the loading procedure differ when students are boarding at the school campus, according to the AAMVA CDL Manual, compared to a loading stop along the route?

School Bus (S) Endorsement • Free CDL Practice Question
Regulation

49 CFR 383.123(a)(2); AAMVA CDL Manual, Section 10.2.2 'Loading Procedures' (campus loading), p. 10-4

Why This Matters

On a crowded school campus with many buses and students moving at once, an idling bus with an unattended ignition is a much bigger risk than on an open route. Turning off the ignition and securing the key specifically in this setting reflects that different environment.