flagman

A traffic guard, traffic controller, flagman, or flagger is a person who directs traffic through a construction site or other temporary traffic control zone past an area using gestures, signs or flags. The person directing traffic is responsible for maintaining the safety and efficiency of traffic, as well as the safety of road workers, while allowing construction, accident recovery or other tasks to proceed. Traffic guards are commonly used to control traffic when two way roads are reduced to one lane, and traffic must alternate. Their duties are to direct traffic to safer areas where construction or traffic incidents are taking place. In addition they have to moderate the traffic density to not cause traffic jams. They guide motorists to follow the traffic laws; but may not be able to enforce the law. Most traffic guards are seen as construction workers; but in some nations, they dress or perform as security guards and police officers. https://en.wikipedia.org/wiki/Traffic_guard