Official MUTCD W20-7 Flagger Ahead Signs

Protect your traffic control personnel with high-visibility Flagger Ahead Signs. We stock the official W20-7 Flagger Symbol and "Flagger Ahead" text warning signs required by MUTCD Part 6. Available in rigid aluminum for long-term projects or portable Reflective Roll-Up vinyl for mobile operations, our Flagger Ahead Signs utilize Fluorescent Orange sheeting to demand driver attention and ensure safe work zone passage.
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Flagger Station Layout & Advance Warning (MUTCD 6E)

The safety of the flagger depends entirely on the "Sight Triangle" and proper advance signage.

  • Sign Spacing (Distance C): The W20-7 "Flagger Ahead" sign must be the final warning device the driver sees before the station. On high-speed roads (55 MPH), install it 500 feet upstream. On low-speed urban streets, 100 feet is the minimum.
  • Line of Sight: The flagger station must be located such that approaching traffic has a continuous view of the flagger for a distance greater than the Stopping Sight Distance (e.g., 495 feet at 55 MPH).
  • The "Escape Route": As shown in the diagram, signs and cones must never block the flagger's ability to retreat to the shoulder. The station must provide an unobstructed path for the flagger to jump clear of an errant vehicle.

Federal Standards for Flagger Ahead Signs

The flagger is the most vital—and vulnerable—component of a temporary traffic control zone. Flagger Ahead Signs (W20-7) are the mandatory advance warning device used to alert motorists that a human traffic controller is managing the flow ahead. Under MUTCD Part 6E, failure to post proper Flagger Ahead Signs before a flagging station is a severe violation that creates immediate liability in the event of an injury or accident.

The W20-7 Standard: Symbol vs. Text

While older job sites used the text-based "FLAGGER AHEAD" (W20-7a), the modern federal standard has shifted to the Symbol Sign (W20-7).

  • The Symbol: Features a black silhouette of a worker holding a flag on a fluorescent orange diamond. This pictorial representation is recognized faster by drivers and overcomes language barriers.
  • Compliance: Both are currently legal, but the W20-7 Symbol is the preferred standard for all Federal-aid highway projects and state DOT operations.

Strategic Placement & "Be Prepared to Stop"

Flagger Ahead Signs are never used in isolation. They are part of a specific safety sequence.

  • The "C" Distance: The sign must be the last sign the driver sees before reaching the flagger. On a 55 MPH highway, it should be placed roughly 500 feet before the flagger station.
  • "Be Prepared to Stop": For high-speed roads, we strongly recommend installing a "Be Prepared to Stop" (W3-4) sign upstream from the Flagger Ahead Sign. This creates a "decision buffer," warning drivers that traffic may be at a dead halt.

Rigid vs. Roll-Up Options

Because flagging operations are often mobile (e.g., utility line work), portability is key.

  • Roll-Up Flagger Signs: Made from Reflective Vinyl or Mesh, these signs mount on portable spring stands. They allow crews to set up and tear down the warning zone in minutes.
  • Rigid Aluminum: Used for stationary flagging stations that will be active for multiple days. Mounted on driven posts for maximum stability.

Reflectivity for Night Operations

Nighttime flagging is extremely hazardous.

  • Fluorescent Orange: The sign must use Fluorescent sheeting to be visible at dusk.
  • Retroreflectivity: For night work, High Intensity Prismatic (Type IV) or Diamond Grade (Type XI) is mandatory. Standard mesh signs (non-reflective) are illegal for use after sunset.

Frequently Asked Questions

Common questions regarding MUTCD compliance, installation standards, and material specifications for regulatory signage.
Can I use a "Men Working" sign instead of "Flagger Ahead"?

No. "Men Working" (or "Workers Ahead") indicates general activity. "Flagger Ahead" indicates that a person is actively controlling traffic flow and that the driver may be required to stop. Substituting one for the other creates dangerous confusion and violates MUTCD Part 6.
How far ahead of the flagger should the sign be?

This depends on the speed limit to allow for "Stopping Sight Distance."

  • Urban (Low Speed): 100 feet in advance.
  • Urban (High Speed): 350 feet in advance.
  • Rural/Highway: 500 feet in advance.
  • The sign must be placed so that the driver has time to perceive the warning and stop before reaching the back of the traffic queue.
Do I need a "Paddle" or a "Flag"?

The Flagger Ahead Sign warns of the person. The person uses the hand-signaling device. The STOP/SLOW Paddle is the primary hand-signaling device required by the MUTCD. Red flags are generally reserved only for emergency situations or low-speed/low-volume roads.

Need specific code assistance?

If your project requires a specific State DOT certification or a specialized variation not listed here, please contact our Compliance Support Team for a custom specification sheet.