Which of the following activities is prohibited while operating a vehicle at the airport?

Using a cell phone without a hands-free device while operating a vehicle at the airport is prohibited due to safety concerns. This regulation is in place to minimize distractions for drivers, ensuring their full attention is on the road and surrounding environment, which is critical in a busy airport setting. The focus on maintaining safety is paramount, as the airport can have complex traffic patterns and numerous pedestrians.

Allowing the use of a hands-free device offers a compromise by enabling communication while keeping the driver's attention on driving. However, using a handheld device diverts attention from the road, increasing the risk of accidents. This regulation aligns with broader traffic safety laws that aim to reduce collisions and enhance overall safety in high-traffic areas like airports.