What is the function of High Intensity Runway Edge Lights (HIRL)?

High Intensity Runway Edge Lights (HIRL) are specifically designed to enhance the visibility of runway edges during critical phases of flight, particularly takeoff and landing. Their primary function is to provide visual guidance to pilots operating at night or in low visibility conditions, ensuring they can clearly identify the runway's boundaries. This is crucial for maintaining safety during these operations, as adequate visual cues allow for accurate approach paths and helps prevent runway incursions.

While other choices highlight various aspects related to airfield operations, they do not accurately describe the primary purpose of HIRL. Continuous guidance to ground vehicles and illuminating the runway at all times are functions associated with other lighting systems. Marking temporary runway closures pertains to signaling that a runway is not in use, rather than providing assistance during flight operations. Therefore, the role of HIRL in facilitating a safe and effective landing and takeoff experience is central to its design and application.