In what scenario would a person controlling traffic signal to indicate that all vehicles must stop?

A person controlling traffic signals indicates that all vehicles must stop by raising both arms high. This maneuver is a universal gesture in traffic control, often recognized by drivers and pedestrians. The raised arms signal a clear and authoritative instruction for all vehicles to halt their movement. This action conveys urgency and commands the attention of drivers, effectively communicating the need for immediate compliance for safety reasons.

Other gestures, such as rotating arms or pointing to the ground, do not convey a clear stop signal and might suggest different instructions or lack clarity altogether. Keeping arms straight out can also designate the need to yield or prepare, but it does not carry the same authoritative stop command as raising both arms high. Therefore, the action of raising both arms high establishes a strong and unmistakable signal for all vehicles to stop.