🔍 Key Concepts

• Bridge light signals for drawbridges and swing bridges in 33 CFR Part 118 (Bridge Lighting and Other Signals) • Difference between a fixed (steady) light and a flashing or changing light as a signal • What indicates a bridge is closed to navigation versus open for vessel passage at night

💭 Think About

• Think about which light indication would clearly and positively tell a mariner, even from a distance, that the span is open and safe to pass through. • Consider whether an extinguished (dark) light is a reliable navigational signal, compared with a positive color or flashing pattern. • Ask yourself which color and pattern are traditionally associated with "safe to proceed" for vessel traffic on U.S. waterways, especially on bridges.

✅ Before You Answer

• Verify in 33 CFR Part 118 what specific light signal means a movable bridge span is open to navigation at night. • Check whether the rule calls for a steady green, a flashing green, or some change from red to green when the span is open. • Confirm whether a red light turning off (extinguished) is ever used as the only official signal that a drawbridge or swing bridge is open.