Advanced Ground Instructor (AGI) Practice Exam 2025 - Free Advanced Ground Instructor Practice Questions and Study Guide.

The "zipper" ground marking is specifically used to indicate the boundaries of a service road. This marking consists of a series of diagonal lines that create a zigzag pattern, which serves to alert pilots and ground vehicle operators to the edges of a service road in the vicinity of the airport. Understanding the function of this marking is crucial for ensuring safe operations on the airfield, as it helps delineate areas where vehicles are permitted versus areas that must remain clear for aircraft movement.

Other markings, such as those indicating the beginning of a taxiway or runway, have distinct characteristics that differ from the zipper marking. For instance, the start of a taxiway might be denoted with solid or dashed lines that lead directly to the taxiway, while runway markings are typically larger and more standardized. Therefore, recognizing the specific purpose of the zipper marking enhances situational awareness and promotes operational safety on the airfield.