What do the different colors of runway lights indicate?

Runway lights are an essential component of an airport's lighting system, serving to provide critical information to pilots during takeoff, landing, and taxiing. The different colors of these lights indicate the status and condition of the runway, specifically whether it is open or closed to traffic.

For instance, green lights typically mark the runway threshold, indicating the beginning of the runway. In contrast, red lights indicate that the runway is closed, directing pilots to exercise caution. Such signaling is crucial for ensuring safety at busy airports and preventing accidents from occurring on closed or obstructed runways.

The other options do not accurately reflect the purpose of runway lights. While weather conditions can influence flight operations, they are not indicated by runway lights. Altitude levels are communicated through other means, such as altimeters or altitude reporting systems, and not through runway lighting. Similarly, runway lights do not categorize or indicate the type of aircraft using the runway; they simply serve the purpose of indicating the operational status of the runway itself. Thus, the correct understanding of runway lights is vital for pilot safety and operational procedures.