What 393.118(d) means in plain language
FMCSR 393.118(d) requires that boulders and similar aggregate materials be secured to your trailer in compliance with specific securement standards. When you're hauling boulders—whether raw stone, riprap, or similar materials—the regulation expects them to be immobilized so they cannot shift, roll, or fall during transport.
This isn't about loose tie-downs or a casual load check. Boulders are heavy, irregular cargo that can cause severe instability and become road hazards if they move during acceleration, braking, or turns. The regulation applies whether you're hauling a partial load or running fully loaded.
What our enforcement data actually shows
Our inspection records show that 393.118(d) is enforced at a dramatically higher severity level than the average FMCSR code. Across 13 million inspections in our database, we tracked 249 all-time citations for this violation. Of those, 247 vehicles were placed out of service—a 99.2% out-of-service rate. This is dramatically above the all-FMCSR average OOS rate of 31.4%.
What's striking: there have been zero citations in both the last 12 months and the last 90 days in our dataset. This suggests either extremely rare enforcement or that the violation has become less common in detected loads. When it does occur, however, the response is swift and severe.
By citation volume across all FMCSR codes, 393.118(d) ranks #1157 of 3,036 codes, making it an uncommon violation—but one with maximum consequences when cited.
Who gets cited most
Our data shows fleets such as J B HUNT TRANSPORT INC (USDOT 80806), BFS ASSET HOLDINGS LLC (USDOT 325981), and SOUTHEAST LOGISTICS & TRANSPORT LLC (USDOT 759891) each with 5 citations over the all-time period. Several other carriers, including STURGEON TRANSPORT INC, KANECA LLC, NOVA LINES INC, and BK JENKINS LLC, have each received 4 citations.
The vehicle makes most frequently cited include Freightliners (76 citations), Peterbilts (43 citations), and Kenworths (30 citations)—largely reflecting the prevalence of these tractors in bulk and aggregate hauling. Trailers cited most often are Fontaine T models (24 citations) and Great Dane units (20 citations), both common in commodity hauling.
How severe is this compared to similar codes
In the Vehicle Maintenance category, 393.118(d) stands apart for its enforcement intensity. Compare it to peer codes: 393.9(a) (inoperable required lamps) has 660,737 all-time citations but only a 15.4% OOS rate. Code 396.3(a)(1) (general inspection/repair/maintenance) has 236,919 citations with a 45.3% OOS rate. Even 393.47E (slack adjuster defective)—a brake safety issue—shows a 0.0% OOS rate across 180,363 citations.
The 99.2% OOS rate for 393.118(d) signals that inspectors treat boulder securement failures as an immediate and critical safety risk, not a correctable deficiency.
How to avoid it
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Pre-trip inspection of aggregate loads: Before you accept a boulder or bulk stone load, physically walk the trailer. Verify that all rocks are tightly wedged or secured with proper blocking, bracing, or securement devices rated for their weight. Do not rely on the shipper's assurance alone.
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Know your load weight and center of gravity: Boulders are dense and irregular. Overloading one side of the trailer or stacking them poorly can create shifting risk during braking or turns. Confirm the load is balanced and does not exceed axle limits.
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Use proper securement hardware: If boulders require straps, chains, or binders, ensure they are in good condition and correctly tensioned. Degraded or loose securing equipment is a common co-factor in cargo violations.
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Inspect straps and chains during your trip: Stop every few hours on long hauls. A visual check of visible securement—straps, chains, blocking—takes 60 seconds and can prevent a citation. Movement or damage during transit is your earliest warning.
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Document the load condition at pickup: Take photos of how the load is secured before you leave the shipper. If an inspector later finds the load has shifted, you have evidence of initial compliance. This protects you if movement occurs due to road conditions outside your control.
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Refuse improperly loaded trailers: You have the authority and responsibility to reject a load that appears unsafely secured. A rejection and a call to dispatch is far better than a 99.2% OOS rate citation.