A school bus driver has run out of safe alternatives and has to reverse, and posts a lookout. What is the lookout there to do?

Explanation

The lookout is there to warn the driver about obstructions, people walking up, and other vehicles, and pointedly not to tell the driver how to steer. The split is deliberate. Only the driver can judge the path the bus will take and how its back end will swing, and a lookout who starts calling the steering substitutes a guess, made from a position where none of that geometry is visible, for the judgment of the one person who can see it. What the lookout offers instead is coverage of the ground the mirrors never reach, and a shout when something moves into it. All of this sits beneath a firmer rule: reversing a school bus is something the guidance actively discourages, to be attempted only when nothing else will shift the vehicle safely, and never at all while there are children outside. With nobody available to act as lookout, the driver sets the brake, kills the motor, pockets the keys, and walks back to see for themselves that it is clear. Where children are being collected, they are aboard before the bus reverses; where they are being set down, the reversing happens first. The wrong options fail two ways. Calling the steering is the one thing the lookout is told to leave alone. Keeping order inside the bus and holding up traffic are both real jobs, but they belong to the driver or to nobody, and neither covers the unseen ground that is the whole reason for posting anyone.

Source: 49 CFR 383.123(a)(2)(iv)