Per the AAMVA manual's evacuation planning guidance, what role is a designated student assistant meant to perform, separate from the driver's own duties?

AAMVA CDL Manual, Section 10.3.2 (Evacuation Procedures) – Be Prepared and Plan Ahead, p. 10-6

A single driver cannot simultaneously secure the bus, direct traffic concerns, and personally walk every student to safety. Designating a responsible student assistant in advance, when one is available, is part of the planning the manual expects before an emergency ever happens.