When do the runway edge lights change color, and what colors do they turn?

The runway edge lights are designed to assist pilots in visualizing the runway's layout, particularly during takeoff and landing. The correct understanding of their functionality is that the lights emit white for the majority of the runway and change to yellow when reaching the last 2000 feet. This color change serves as a warning to pilots, indicating that they are approaching the end of the usable runway, enhancing safety and awareness during landing.

While the other options suggest various scenarios regarding color changes and their meanings, they do not align with standard practices governing runway edge lighting. For instance, one option incorrectly states that lights are always green to white or that they would emit red at all points, which is not the case. Additionally, the reference to yellow lights indicating a runway change does not capture the specific function of the runway edge lights in alerting pilots about their proximity to the runway's end.

Understanding this aspect of aviation infrastructure is crucial for ensuring effective communication and safety during critical phases of flight.