Stationary object hazards are marked by what type of indication?

Stationary object hazards are indicated by a three-sided solid sign, which is typically mounted on a pole. This type of sign is designed to be highly visible and effectively communicates the presence of a hazard to individuals approaching the area. The three-sided shape provides a definitive warning that catches attention from multiple angles, enhancing the likelihood that it will be noticed.

In contrast, a solid circular sign is generally reserved for regulatory or informational purposes rather than specifically signaling hazards. A red square flag may be used for various signaling or marking purposes but does not specifically indicate stationary object hazards. A flashing light, while effective in drawing attention, is more commonly associated with dynamic warnings such as those for moving hazards or alerts rather than for marking stationary objects. The three-sided solid sign, therefore, serves the critical function of clearly indicating the presence of potential dangers associated with stationary obstacles.