flagman
A person who uses signals to safely direct traffic.
A flagman is a person who uses flags or signal lights to direct traffic, typically at construction sites or railroad crossings. When workers need to repair a road or lay down new pavement, a flagman stands at each end of the work zone, holding a large stop/slow paddle or waving colored flags to tell drivers when to stop and when to proceed carefully through the area.
Flagmen wear bright orange or yellow vests so drivers can spot them easily. They need to stay alert and focused because they're responsible for keeping both the construction workers and the passing drivers safe. A flagman might signal cars to stop while a large truck backs up, or wave traffic through slowly while workers move equipment off the roadway.
The job requires good judgment and clear communication. A flagman must watch traffic coming from both directions, understand what the work crew is doing, and make quick decisions about when it's safe for vehicles to pass. On a hot summer day, you might see a flagman standing in the sun for hours, patiently guiding an endless stream of cars around a road crew.
At railroad crossings, a flagman might protect workers who are repairing tracks by stopping road traffic when necessary, though today automated signals and gates handle most of this work.