Which purpose does the indicate colors of drawbridge signs serve?

The colors of drawbridge signs primarily serve to communicate the status of the bridge. This system of color coding is crucial for navigation safety, as it informs boaters and engineers whether the bridge is open or closed, and if it is safe to navigate under it. When the bridge is closed to marine traffic, specific colors might be displayed to signal that vessels must wait. Conversely, when the bridge is open, different colors indicate that vessels may pass freely. Understanding these signals is vital for ensuring safe passage and preventing accidents on the water.