During nighttime flagging, what must be true about all flagging equipment, including vests and paddles?

Answer: D — Retroreflective

To be seen at night, flagging gear must bounce driver headlights back toward the source. Retroreflective materials do this by design, using tiny beads or prism structures to return light directly back to the driver, so vests and paddles remain highly visible from a distance even in darkness. Fluorescent or neon colors help in daylight but don’t reliably reflect headlights at night, so they aren’t sufficient alone. Reflective tape can be retroreflective, but the essential requirement is that the equipment itself is retroreflective, ensuring all gear used by the flagger provides that nighttime visibility.