What color must the lighted portion be for flaggers' flashlight?

• A. Blue.
• B. Red.
• C. Green.
• D. White.

Answer: (B)

Red is used for the lighted portion of a flagger’s flashlight because it clearly signals drivers to stop and is widely recognized as a stop cue in traffic control. This color choice helps maintain easy, unambiguous communication, especially at night or in low-visibility conditions. Other colors could be misinterpreted or confuse drivers (blue or green signals can resemble other signals or authorities; white can create glare and reduce night vision), so red is the standard for flagger signaling.