Flagging Operations
Flaggers are the most exposed workers in the zone, so the C-31 exam is precise about how they signal and where they stand.
The paddle
The STOP/SLOW paddle is the primary and preferred device (a flag is for emergencies only). Standard minimum size 18 × 18 in; 24 × 24 in where greater emphasis is needed and speeds ≥ 30 mph. The STOP face is red with white letters; the SLOW face is orange with black letters.
The three paddle methods: show the STOP face with the free arm raised, palm out, to stop traffic; show the SLOW face and motion with the free hand to let traffic proceed; show the SLOW face to alert and slow traffic. A flag, when an emergency forces its use, must never signal traffic to proceed.
The flagger station
- Located so approaching drivers have enough stopping sight distance to stop.
- Preceded by advance warning signs (except in emergencies).
- Illuminated when flagging at night.
- The flagger should identify an escape route, stand alone and clearly visible, and stay out of the open lane until traffic has stopped.
Practice: Flagging Operations
Frequently asked
What is the minimum size of a STOP/SLOW paddle?
When may a flagger use a flag instead of a paddle?
What does a flagger station require at night?
More C-31 Traffic Control topics
Planning & Estimating Traffic Control
C-31 study guide on planning a traffic control zone: the four TTC areas, taper-length formulas, buffer space, advance warning sign spacing, and estimating devices.
Read & practice →Notifications, Permits & Coordination
C-31 study guide on permits and coordination for traffic control work: encroachment permits, 811/USA excavation notice, agency and public notification, and closure windows.
Read & practice →Work-Zone Signs & Markings
C-31 study guide on work-zone signs: orange sign color, sign shapes, common MUTCD codes (W20-1, W20-7, W3-4, G20-2), nighttime retroreflectivity, and changeable message signs.
Read & practice →Channelizing Devices & Arrow Boards
C-31 study guide on channelizing devices: cone and drum heights, barricade types, vertical panels, device spacing on tapers and tangents, and arrow board modes.
Read & practice →Transportation & Training
C-31 study guide on transporting traffic control devices and training requirements: flagger training before assignment, what training covers, and where it is documented.
Read & practice →Worker Safety & PPE
C-31 study guide on work-zone worker safety: high-visibility apparel classes, OSHA accident-prevention sign colors, struck-by hazards and the Focus Four, and night-work lighting.
Read & practice →