What is the definition of the straight back hand signal in reference to operating apparatus in reverse?

The straight back hand signal, particularly in the context of operating apparatus in reverse, is characterized by holding one hand above the head with the palm facing toward one's own face and waving it backward. This specific motion clearly communicates to the driver that they should proceed in a straight back direction. It serves a dual purpose: enhancing visibility of the signal from a distance and ensuring that the driver understands the intention to reverse without deviating left or right. Clarity in communication is vital when operating large fire apparatus, especially in potentially tight or hazardous environments, making this hand signal particularly important for safety.