What is the purpose of taxiway lead-on and lead-off lights?

Taxiway lead-on and lead-off lights are specifically designed to assist pilots in safely transitioning between runways and taxiways. Their primary function is to provide visual cues that guide aircraft from the runway onto the taxiways or vice versa. These lights mark the path that aircraft should follow to ensure they are on the correct route, helping to prevent potential runway incursions or collisions with other aircraft and ground vehicles.

Option A, related to air traffic control instructions, does not accurately capture the function of these lights, as they are not used for communication of ATC directives but rather for visual navigation. Options C and D focus on runway illumination and dimensions, which pertain to different safety and operational needs that are not achieved through lead-on and lead-off lighting. By clearly marking the transitions between runways and taxiways, lead-on and lead-off lights enhance situational awareness for pilots on the ground and contribute to overall airfield safety.