From South Dakota Department of Transportation Standard Specifications for Roads & Bridges:
"The Contractor shall furnish certified flaggers to perform project traffic control. The minimum age for flaggers shall be 18 years old. Flagger training and certification is available at some
Department Area offices and from the Associated General Contractors (AGC). All flaggers shall complete a flagger training course and pass a written test to become certified. Flagger
certification is valid for a period of two years. All flaggers shall be certified in South Dakota prior to flagging on the project. Flaggers shall carry proof of certification while flagging on Department projects."