What do red runway entrance lights signify?

Red runway entrance lights are an important visual cue used to indicate a critical safety measure at airports. Specifically, these lights signify that it is not safe to cross the runway. This warning helps prevent potential collisions by signaling to drivers or vehicles that the runway is currently active and that crossing should be avoided.

Recognizing the presence of red lights is crucial, as they alert operators to the need to yield to approaching aircraft. The effectiveness of red runway entrance lights lies in their universal recognition; they serve as a standard warning system that communicates the necessity of caution in areas where aircraft may be taking off or landing, ensuring the safety of both ground traffic and air operations.

Other cues, like green lights, would indicate that it is safe to proceed, which clarifies the importance of red lights as indicators of restricted access at critical points near runways.