What is the main reason for requiring high-visibility vests on the airside?

The requirement for high-visibility vests on the airside primarily revolves around safety. These vests are designed to enhance the visibility of workers among other vehicles and personnel operating in the often-busy and potentially hazardous airport environment. By ensuring that operators are easily recognizable, the vests help prevent accidents by allowing pilots, ground crew, and other vehicle operators to see the personnel clearly, even from a distance or in low-light conditions.

While identifying staff roles, promoting branding, or indicating vehicle sizes might have some relevance in specific contexts, the critical factor remains the safety aspect associated with visibility. Ensuring that all personnel are easily seen reduces the risk of mishaps and contributes to a safer operational environment on the airside.