When backing up, which of the following is most critical to check?

When backing up, checking blind spots is the most critical factor because they represent areas around the vehicle that may not be visible through mirrors or a rearview camera. Drivers can often overlook pedestrians, cyclists, or other smaller vehicles that could be in these blind spots, leading to accidents.

While side mirrors, rearview cameras, and awareness of traffic behind you are important for safe backing procedures, they do not provide a complete view of the surrounding area. Relying solely on side mirrors or a rearview camera can give a false sense of security, as these devices may not capture everything directly to the sides or immediately behind the vehicle. Therefore, actively checking blind spots helps ensure that the driver is aware of all potential hazards before moving the vehicle, significantly enhancing safety during the maneuver.