Why is it important to use a helper when backing up?

Using a helper when backing up is essential primarily because there are blind spots that a driver cannot see. Large vehicles, such as trucks and buses, often have significant blind spots that obstruct the driver's view of other vehicles, pedestrians, or obstacles behind them. These areas can pose a risk of accidents if the driver relies solely on their mirrors, which may not give a complete picture of their surroundings.

Having a helper can greatly mitigate the risk associated with these blind spots. The helper can provide real-time feedback and guidance about the surroundings, allowing the driver to maneuver safely without missing critical visual cues. This collaborative approach enhances the safety of the backing process, ensuring that all potential hazards are accounted for before and during the vehicle's movement.

While other choices touch upon relevant concepts, they do not capture the importance of blind spots clearly and concisely as the correct answer does.