What does the Stop Bar consist of?

The Stop Bar is designed to provide visual indications to pilots at taxiways or runway holding positions, helping to ensure safety and compliance with air traffic control instructions. The correct response specifies that the Stop Bar consists of a row of unidirectional in-pavement red lights accompanied by an elevated red light on each side of the taxiway. This configuration is critical as the red lights signal to the pilots to stop and not proceed further along the taxiway, which is essential in preventing incursions onto active runways or other restricted areas.

This set-up not only enhances visibility for pilots during both day and night operations but also reinforces the message of stopping clearly, as both the in-pavement lights and the elevated lights create a consistent visual cue. The presence of red lights is universally recognized in aviation as a stop indication, making this system an integral part of airport ground movement safety protocols.