A flashing red light displayed at a single...

A flashing red light displayed at a single...

Question 1 of 2707066636ee928f7522a1c519749

A flashing red light displayed at a single lock means that the lock __________.

Question 1 of 27070

Q

A flashing red light displayed at a single lock means that the lock __________.

🔍 Key Concepts

• Lock traffic signals used on U.S. inland waterways • Difference between a lock being ready for use and whether vessels may approach or must stand clear • How flashing vs steady red or green lights are typically used in control signals

💭 Think About

• Think about what a red light normally indicates for vessel or vehicle movement, and how a flashing version might modify that meaning at a lock • Consider the safety reasons: when would the lock master want all vessels to stay well away from the lock versus just waiting close by? • Ask yourself: does a flashing red signal suggest that the lock is available now, or that there will be a delay before it can be used?

✅ Before You Answer

• Verify what red vs green vs amber/yellow mean specifically in a lock signal system (not in general navigation lights) • Check which signal means the chamber is ready and open for entry versus not yet ready • Confirm whether a flashing red allows vessels to approach or requires them to stand clear until a different signal is shown