How should a flagger communicate a stop command to oncoming traffic?

• A. By flashing headlights only.
• B. By using the STOP hand signal, supported by a whistle if needed, and clear, authoritative gestures.
• C. By shouting 'Stop' from a distance.
• D. By waving both arms in a circular motion.

Answer: (B)

Communicating a stop command requires a standardized visual signal reinforced by an audible cue when needed. The flagger should use the STOP hand signal—arm extended toward oncoming traffic with the palm facing them—supported by a whistle if distance or noise makes the signal hard to see or hear, and couple it with clear, authoritative gestures. This combination provides a consistent, unambiguous cue that drivers can recognize and respond to quickly, which is crucial for stopping safely in the work zone. Relying on flashing headlights alone can be misread or missed, shouting from a distance is unclear and intrusive, and waving arms in a circular motion has no defined meaning and can confuse drivers. The STOP signal with a whistle gives both a clear visual and an audible command, ensuring a safe, controlled stop.