By: KC Pawling, Road Safety and Loss Prevention Specialist
County road systems often present unique safety challenges, particularly when temporary hazards develop such as washed-out shoulders, culvert failures, soft spots, or edge drop-offs. In many cases, crews rely on flags to alert motorists and maintenance personnel to these conditions. While flagging can be an effective first step, not all flags provide adequate warning. In fact, improper flag use can increase liability rather than reduce it.
To truly protect the traveling public and limit exposure, flags must be selected and used with attention to size, visibility, placement, and overall effectiveness. Just as important, they need to be part of a broader approach to hazard awareness that aligns with established safety standards.
Flags are intended to serve as a temporary visual warning, helping draw attention to abnormal or unsafe roadway conditions until repairs can be completed or more formal traffic control measures are installed. The Manual on Uniform Traffic Control Devices (MUTCD, 11th Edition) emphasizes that drivers must be given enough time to see, recognize, and respond to hazards. A flag that lacks visibility or is poorly placed does not meet that expectation.
When using flags to alert drivers to temporary road hazards, consider the following:
Size and material. One of the most important factors is size. Flags used for roadway hazards should be large enough to be seen clearly at normal travel speeds and distances. A commonly accepted minimum is 18 inches by 18 inches, although larger flags are often more effective. These should be made of durable, weather-resistant material. Larger flags also tend to move more in the wind, which helps catch a driver’s attention.
Color/visibility. Color and visibility are equally important. Fluorescent orange is widely recognized as the standard color for temporary traffic control and roadside hazards, consistent with MUTCD work zone principles. This color stands out in most environments and signals caution to drivers. For conditions that extend into nighttime or low-light periods, adding retroreflective material or supplemental visibility devices becomes essential. The goal is not just to make the flag visible, but to ensure it is immediately recognized as a warning.
Positioning. How and where flags are placed can make the difference between an effective warning and one that is easily missed. Flags should be mounted high enough—generally 36 to 48 inches above the ground or higher depending on vegetation or terrain—to remain in a driver’s line of sight. They should be placed on the same side of the road as the hazard. Rather than relying on a single flag, crews should consider using multiple flags to define or “frame” the hazard area. This creates a clearer visual cue and improves a driver’s ability to understand the situation ahead. On higher-speed county roads, providing advance notice through spacing becomes especially important, as drivers need additional time to react.
Types of Flags to Avoid. It is also important to understand what not to use. Small utility locate flags, while common on job sites, are not designed for traffic warning. Their limited size, low height, and intended purpose for close-range identification make them ineffective for alerting drivers. When these flags are used in place of proper hazard markers, they can create a false sense of security. If a driver cannot reasonably detect a hazard in time to respond, the marking has failed—and from a liability standpoint, that can be significant.
When a Flag is Not an Adequate Warning. Another key consideration is recognizing when flags alone are not enough. Flags should be viewed as a temporary or supplemental measure rather than a complete solution. If a hazard is more severe, persists for an extended time, or encroaches into the traveled portion of the roadway, additional traffic control devices should be used. This may include warning signs such as “Soft Shoulder” or “Road Edge Drop-Off,” as well as cones, drums, or delineators. In more complex situations, a temporary traffic control plan may be necessary to align fully with MUTCD Part 6 requirements.
Environmental Conditions. Visibility must also be maintained under changing conditions. Hazards do not disappear when sunlight fades, and neither should their warnings. When flags remain in place overnight or during periods of poor visibility such as rain, fog, dust, or snow, additional measures like retroreflective materials or object markers should be used. Ensuring visibility at all times supports both safety and compliance with established standards.
Need for Continuous Monitoring. Ongoing inspection and maintenance are critical to keeping flagging effective. Flags should be checked regularly, particularly after storms, strong winds, or heavy traffic activity. A flag that is torn, faded, knocked down, or obscured by vegetation no longer provides meaningful warning. Prompt replacement or adjustment is necessary to maintain effectiveness. At the same time, it is equally important to remove flags once a hazard has been corrected. Leaving outdated warnings in place can reduce driver trust and lead to complacency.
Documentation. From a risk management perspective, documentation and consistency play an important role. Recording when hazards are identified, how they are marked, and when they are corrected helps demonstrate due diligence. Taking photos of proper flag placement can provide additional support if questions arise later. Just as important, crews should apply consistent practices across the county so that drivers can quickly recognize what flagged hazards mean, no matter where they are traveling.
Regulatory Requirements. Although flags themselves are not heavily detailed as standalone devices in regulations, their use is guided by broader safety principles found in the MUTCD, ANSI visibility standards, OSHA requirements, and ATSSA best practices. All of these emphasize the same underlying message: hazards must be clearly visible, understandable, and appropriately marked to give road users time to react.
In the end, properly marking roadside hazards is not just a routine task, it is a critical piece of public safety and liability prevention. Taking the time to use the right size flags, placing them correctly, and supporting them with appropriate traffic control measures can make a meaningful difference. Simply put, if drivers cannot see a hazard in time to react, it is not effectively marked.
If you need a training scheduled, or just simply want help developing or improving your safety and training program, you can contact me via email at kcpawling@nirma.info or phone at 402-310-4417.
