Which of the following items is critical for a signal person to possess during their duties?

Clear visibility of the work area is essential for a signal person because it directly affects their ability to communicate effectively and ensure safety on the job site. A signal person is responsible for guiding equipment operators and helping them maneuver loads safely. This requires a comprehensive understanding of the entire work environment, including the movements of both the machinery and other workers.

Having clear visibility enables the signal person to assess potential hazards, monitor the progress of the load being moved, and provide timely and accurate signals to the operator. If visibility is compromised, the risk of accidents increases, as the signal person may not be able to see obstacles or changes in the work area that could pose dangers.

In contrast, while a cell phone or a clipboard might be useful tools for communication or note-taking, they do not replace the critical need for visual awareness. A whistle can also aid in providing audible signals but does not substitute for the visual oversight required in ensuring a safe operation. Overall, maintaining clear visibility is paramount for executing the responsibilities of a signal person effectively.