What 393.118B means in plain language
FMCSR 393.118B addresses the secure transport of boulders in commercial trucks. The regulation requires that boulders be fastened, braced, blocked, or otherwise prevented from shifting, sliding, or falling during transport. This is part of the broader cargo securement framework that applies when you're hauling heavy or irregularly shaped loads.
Boulders—whether quarried stone, aggregate, or landscaping material—pose a particular challenge because of their irregular shapes, weight distribution, and tendency to roll or settle during transit. Unlike packaged goods or palletized cargo, boulders demand deliberate securement methods tailored to their specific dimensions and weight. The regulation doesn't allow you to simply load them and assume gravity will hold them in place.
If an inspector finds that your boulders are not secured in accordance with the applicable securement rules, you will be cited. The citation reflects a failure to prevent cargo shift, which creates a safety hazard for your vehicle, other road users, and potentially yourself.
What our enforcement data actually shows
This violation is exceptionally rare in our database of 13 million+ roadside inspections. Across all time, our records show only 5 citations for 393.118B. In the last 12 months, we logged 2 citations; in the last 90 days, just 1.
What makes this code stand out is its enforcement severity: every single citation in our data resulted in an out-of-service (OOS) placement. The OOS rate for 393.118B is 100.0%—meaning if you are cited, your truck will be taken out of service. This is dramatically higher than the all-FMCSR average OOS rate of 31.4%, and it reflects the gravity regulators place on cargo securement failures.
393.118B ranks #2406 out of 3,036 FMCSR codes by citation volume, placing it in the bottom 20% of enforcement actions. The rarity of citations does not, however, indicate lenience. Rather, it suggests that most carriers successfully secure boulders correctly—and those who do not face immediate removal from service.
Who gets cited most
Over the last 180 days, our data shows citations in Iowa (IA) and North Carolina (NC), with 1 citation each. Both inspections resulted in out-of-service placements at a 100.0% rate.
Across all time, our records identify five carriers with one citation each: CRST EXPEDITED INC (USDOT 53773), A M COHRON & SON INC (USDOT 222009), DMT TRUCKING LLC (USDOT 795982), FLORES ENTERPRISE LLC (USDOT 3003238), and TRUCK'EM LLC (USDOT 4190638). The presence of these citations in our database reflects isolated enforcement events; no single carrier shows a pattern of repeated violations.
How severe is this compared to similar codes
393.118B falls within the Vehicle Maintenance category of FMCSR codes. Comparing it to other codes in that category reveals important context.
Inoperable required lamps (393.9(a)) has generated 660,737 citations with a 15.4% OOS rate—vastly higher citation volume but a much lower severity outcome. General inspection/repair/maintenance violations (396.3(a)(1)) show 236,919 citations and 45.3% OOS rate. These codes affect many thousands of trucks annually.
By contrast, slack adjuster defects (393.47E) and proof of periodic inspection violations (396.17C-PI and 396.17(c)) register in the hundreds of thousands of citations but carry 0.0% OOS rates, indicating administrative or minor mechanical findings.
The 100.0% OOS rate for 393.118B places it at the severe end of the enforcement spectrum, despite its low overall volume. This indicates that when inspectors cite cargo securement failures with boulders, they regard the condition as immediately unsafe and non-negotiable.
How to avoid it
Securing boulders properly begins before you leave the shipper and continues through your pre-trip inspection:
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Verify load securement at pickup. Before departing, physically walk around the load and confirm that each boulder is blocked, braced, or strapped according to the shipper's securement plan. Do not assume the loader got it right. Look for gaps, shifting, or unsupported edges.
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Check all straps, chains, and binders. Inspect each securement device for damage, corrosion, or wear. Ensure fasteners are tight and that no strap or chain is frayed, cut, or compromised. Carry backup securement material in case you need to re-secure during transit.
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Distribute weight evenly across the bed. Boulders of similar size and weight should be arranged to balance the load side-to-side and front-to-back. Uneven weight increases the likelihood of shift and roll during braking or cornering.
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Use friction-reducing mats and edge protectors. If your cargo securement plan calls for them, deploy mats under boulders to prevent sliding and edge protectors where straps or chains contact stone. These are inexpensive insurance against cargo movement.
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Perform en-route checks during long hauls. After your first 50 miles and every 2–3 hours thereafter, stop and visually inspect your load. Look for strap slack, chain kink, or any sign that a boulder has shifted. Retighten if needed.
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Know your vehicle's load limits. Overloading a truck bed reduces traction and increases braking distance. Verify that total cargo weight—including boulders—does not exceed your vehicle's GVWR or axle limits. Excessive weight makes load shift more likely.
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Be aware of driver fatigue signals. Our co-occurring violation data shows that two inspections citing 393.118B also included citations for operating while fatigued (392.2). Fatigue impairs judgment about load security and increases risky driving that can jostle cargo. If you are tired, do not drive; secure a place to rest or hand off the load to a rested driver.
Because boulders are heavy, irregular, and prone to rolling, there is no room for guesswork. Invest the extra 10 minutes to inspect your securement before departure and at major stops. A citation for 393.118B will take your truck out of service and disrupt your schedule far more than a careful pre-trip check will.