What purpose do hold lines serve on helipads?

Hold lines on helipads are critical for ensuring safe and efficient operations in helicopter landings and takeoffs. They serve as clear visual indicators for pilots, providing precise locations where helicopters can land. This helps maintain a structured flow of traffic, ensuring that all aircraft adhere to established landing zones, thereby minimizing the risk of accidents or conflicts with other aircraft.

While other choices mention traffic management and vehicle access, they don't specifically address the primary role of hold lines in relation to helicopter landing operations. Therefore, indicating where helicopters can land is the most accurate description of their function.