What is NOT an acceptable indicator when lighted lamps are not in use?

Traffic cones are used to direct and manage traffic, marking off areas where caution is needed, but they do not provide an effective warning indication when lighted lamps are not in use. Unlike flares, reflectors, and red flags, which are specifically designed to be highly visible and to convey information about the presence of potential hazards, traffic cones primarily serve as physical barriers.

Flares emit light and are intended to signal an emergency or alert drivers to potential danger. Reflectors, especially in low-light conditions, enhance visibility by reflecting light back to its source. Red flags can signal caution or stop, making them recognizable indicators of danger. Traffic cones, while useful for physical delineation, do not communicate the same level of warning or visibility in situations where lighted lamps are absent, making them the less suitable choice in this context.