What color are the RWY edge lights?

The edge lights for runways (RWY) at airports, including O'Hare, are indeed white. These lights serve a critical role in the safe operation of aircraft, particularly during low visibility conditions or at night. White runway edge lights outline the perimeter of the runway, helping pilots to clearly see the boundaries and align their approaches safely.

The other colors listed, while relevant in certain contexts, do not represent runway edge lighting. Green lights typically indicate the start or threshold of a runway, blue lights are associated with taxiway edges, and red lights are used to denote the ends of runways where they should not be crossed during landing or takeoff. Understanding the specific functions of these colors is essential for recognizing their importance to aviation safety.