What does a green light on a drawbridge signify?

A green light on a drawbridge signifies that the bridge is open and locked in a position to allow boat traffic to pass safely underneath. This is an important navigational aid for mariners, indicating that they have the right of way and can proceed without stopping or waiting for the bridge to open.

Understanding the signaling on drawbridges is crucial for safe navigation, as it helps to prevent accidents and ensures efficient movement between vessels and land traffic. The presence of a green light means that boaters can confidently maneuver under the bridge, knowing that it is in a secure position. The other options do not accurately represent what the green light signifies in relation to drawbridge operations.