What 393.87(b) means in plain language
This regulation requires that any cargo extending beyond the rear or sides of your truck bed or trailer must be marked with warning flags. The flags serve a critical safety function: they make your vehicle's actual dimensions visible to other drivers, especially in poor lighting or when they're approaching from angles where the extended cargo might not be obvious.
The regulation applies whether your load projects a few inches or several feet. A single missing or non-functional flag can result in a citation. The flags must be visible and in good condition—faded, torn, or absent flags don't meet the requirement.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.87(b) citations are uncommon. We have logged 241 total citations for this violation in our database history. Over the last 12 months, we recorded zero citations, and in the last 90 days, zero citations. This suggests either extremely low violation rates in the field or very selective enforcement.
When 393.87(b) violations do result in an out-of-service order, it happens rarely. Our data shows 5 out of 241 citations led to out-of-service placement, yielding a 2.1% OOS rate. This is substantially lower than the all-FMCSR average OOS rate of 31.4%, indicating that inspectors view this as a lower-severity maintenance defect that doesn't typically justify immediate vehicle removal from service. Code 393.87(b) ranks #1169 out of 3,036 FMCSR codes by citation volume, placing it well below the enforcement focus of more common violations.
Who gets cited most
Our inspection records show fleets such as J B Hunt Transport Inc and Bennett Truck Transport LLC each with 3 citations for this violation. The enforcement pattern is highly dispersed—no single carrier dominates, and the top carrier accounts for only a small fraction of all citations. This distribution suggests the violation occurs across carrier types and sizes, rather than clustering in a particular fleet segment.
The top vehicle makes cited include Freightliner (12 citations), Peterbilt (10 citations), Western Star and Mack (8 citations each), and Fontaine, Kenworth, International, Trailer, and Volvo (6–7 citations each). This mix reflects the general population of heavy-duty trucks on the road and does not single out any particular manufacturer as especially prone to this violation.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, 393.87(b) is mild by enforcement volume and severity. For comparison, code 393.9(a)—inoperable required lamps—has generated 660,737 citations with a 15.4% OOS rate, roughly 2,700 times more frequent and nearly 8 times more likely to result in out-of-service status. Code 396.3(a)(1), covering general inspection and repair defects, shows 236,919 citations and a 45.3% OOS rate, indicating much stricter enforcement. Even code 393.11, covering lighting devices and reflectors, has 179,734 citations and a 1.8% OOS rate—still higher enforcement volume than 393.87(b).
The low OOS rate on 393.87(b) places it alongside codes like 396.17(c) (no proof of periodic inspection, 0.0% OOS) and 393.78 (windshield condition, 0.3% OOS), suggesting that inspectors treat missing load flags as a defect requiring correction but not immediate removal from service.
How to avoid it
Before every trip:
- Walk around your loaded vehicle and check for any cargo extending beyond the rear bumper or side edges of your bed or trailer.
- Inspect existing warning flags for tears, fading, or loss of reflectivity. Replace any that are visibly worn.
- Verify flags are securely attached and will not flap loose during transit.
- If using tarps or covers, ensure they don't obscure warning flags or make them ineffective.
During load securement:
- Position cargo within the vehicle footprint whenever possible. If projection is unavoidable, install flags before the vehicle leaves the lot.
- Use high-visibility warning flags that meet DOT color standards (typically red and white or fluorescent colors).
- Install flags at all four corners of the projecting load (both sides and rear corners) if the load extends beyond the vehicle sides.
- Test flag visibility from a distance and in different lighting conditions, especially at dusk or dawn.
Maintenance habit:
- Check flags monthly as part of your pre-trip routine, even if no cargo is currently projecting.
- Keep spare replacement flags in your vehicle so you can swap damaged ones immediately.
- Document your flag inspection in your vehicle maintenance log to establish a compliance record.