What markings do not require retroreflective glass beads?

The markings that do not require retroreflective glass beads are the overrun chevrons and closed pavement markings. These types of markings are typically used in scenarios where their primary function is to convey information about the status of the runway or taxiway rather than to provide guidance during low visibility conditions, which retroreflective materials would assist with.

Overrun chevrons are indicated on the runway to mark areas that are not to be used for landing or takeoff, essentially providing a visual queue that enhances safety by indicating where aircraft should not proceed. Closed pavement markings signify areas of the runway or taxiway that are blocked off from use, meant to keep aircraft clear of those zones. The visibility of these markings is crucial, but they are not used in situations where retro-reflectivity is necessary, unlike runway and taxiway markings that must be visible during both day and night and in adverse weather conditions.

In contrast, taxiway and shoulder markings, runway and threshold markings, and airplane hold short lines are vital for guiding pilots and require retroreflectivity to ensure they are noticeable under various lighting conditions. Thus, option D stands out as the correct choice, as it serves a different purpose that does not necessitate the use of retroreflective glass