🔍 Key Concepts

• 33 CFR Part 118 – Bridge Lighting and Other Signals (especially signals for drawbridges and vertical lift bridges) • The difference between “span is moving or not ready” vs “span is fully open and safe to pass” signals • Meaning of steady vs flashing lights and colors (red, green, white, yellow) on bridges

💭 Think About

• Which color is most commonly associated with a safe passage / open channel indication on aids to navigation and bridge signals? • Does a flashing red light usually mean "safe to go" or "danger/stop" in the maritime context? Think about how that applies to a moving bridge span. • For a bridge span, would the signal for "fully open" be more likely located on/under the movable span itself or somewhere off to the side?

✅ Before You Answer

• Verify in 33 CFR 118 what light configuration is specified to show that a movable (lift) span is fully open. • Check which answers mention lights directly under or on the movable span, not just anywhere on the bridge. • Eliminate any option where the light color or pattern is typically used for warning, danger, or caution rather than "open and clear to pass."