Final answer:
This sign indicates the clearance or vertical distance from the road surface to a bridge or overpass.
Step-by-step explanation:
This sign indicates the clearance or vertical distance from the road surface to a bridge or overpass. It is important for vehicles to know this distance so that they can avoid any collisions or damages while passing under the bridge. This sign is a safety precaution to prevent overheight vehicles from attempting to pass through a bridge or overpass that they cannot safely clear.