Describe the procedure for safely backing up a commercial vehicle.

The procedure for safely backing up a commercial vehicle is crucial for preventing accidents and ensuring the safety of the driver and others around the vehicle. Using a spotter, if available, is a recommended practice as it provides an extra set of eyes that can help guide the driver when visibility is limited. The spotter can communicate instructions and alert the driver to any obstacles or pedestrians in the vicinity.

Frequently checking mirrors is equally important because it allows the driver to maintain awareness of the vehicle's surroundings. Mirrors provide a view of areas that may not be visible through the rearview camera or the driver's direct line of sight. This dual approach—utilizing both a spotter and mirrors—ensures the driver has the best chance of detecting any potential hazards while reversing.

The other choices do not encompass best practices for safe backing. Relying solely on rearview cameras can be risky, as these devices may not show everything in the vicinity and can fail or provide a limited perspective. Backing up quickly increases the risk of accidents as it reduces the driver's ability to adequately assess the surroundings. Finally, depending only on side mirrors overlooks the importance of the vehicle's overall spatial awareness that both side and rearview mirrors can provide.