When reversing a vehicle, what should be operational for safety?

When reversing a vehicle, having the backup alarm operational is crucial for safety. The backup alarm is designed to alert pedestrians and other individuals in the vicinity that the vehicle is in reverse, thus preventing accidents. This auditory warning helps to make those nearby aware of the vehicle's movement, particularly in busy or crowded environments where visibility might be limited.

While headlights, windshield wipers, and turn signals are important for vehicle operation and safety in different contexts, they do not specifically serve the function of alerting others to a reversing vehicle. Headlights are primarily for visibility in low light conditions, windshield wipers are used for clearing the driver's view in rain or adverse weather, and turn signals are intended for indicating direction during driving rather than specifically for reversing maneuvers. Therefore, the primary safety feature when backing up is the backup alarm, as it plays a key role in preventing potential collisions.