What 393.118D means in plain language
FMCSR 393.118D requires that boulders—large rocks transported as cargo—be secured according to specific securement rules outlined in the federal motor carrier safety regulations. The regulation exists because unsecured or improperly secured boulders can shift during transport, causing load imbalance, vehicle instability, or worst-case cargo spillage that endangers other road users.
The rule doesn't say you can't haul boulders. It says that when you do, the securement method—whether chains, straps, blocks, or other devices—must meet federal standards designed to keep the load in place under normal driving conditions, emergency braking, and turns. If an inspector finds that your boulders aren't held down or restrained according to those standards, you'll be cited.
What our enforcement data actually shows
Across 13 million inspections in our database, 393.118D is rarely cited. We have recorded 4 all-time citations for this code, with 4 citations in the last 12 months and 0 in the last 90 days. The rarity of enforcement doesn't mean the rule doesn't matter—it means most drivers and carriers comply.
What stands out: every one of the 4 citations we've recorded resulted in an out-of-service order. That's a 100.0% out-of-service rate, far exceeding the all-FMCSR average of 31.4%. When inspectors cite 393.118D, they're not issuing warnings—they're taking the vehicle out of service until the issue is fixed. This reflects how seriously federal safety officials view improperly secured heavy boulders.
Ranked against all 3,036 FMCSR codes by citation frequency, 393.118D sits at #2480. It's a low-volume code, but the enforcement action is unambiguous when violations occur.
Who gets cited most
Our inspection records from the last 180 days show Illinois with 1 citation, resulting in 1 out-of-service order (100.0% OOS rate). The data set is small—only one state has a recorded citation in our recent window—which means any operator in any state should assume equal scrutiny if they're hauling boulders.
Across all-time data, carriers including Republic Companies, Tommy P Roberts, In & Out Services LLC, and Drone Transportation Inc each appear in our records with citations for this code. These aren't patterns of systemic non-compliance; rather, they reflect that boulder transport happens sporadically and securement citations are isolated events. The lesson: any fleet hauling boulders is subject to the rule.
How severe is this compared to similar codes
Bouldersecurement sits in the Vehicle Maintenance category alongside codes like 393.9(a) (Inoperable required lamps: 660,737 citations, 15.4% OOS rate) and 396.3(a)(1) (Inspection/repair/maintenance: 236,919 citations, 45.3% OOS rate). While those codes generate far higher citation volume, 393.118D's 100.0% OOS rate is markedly stricter. Comparatively, 393.11 (Lighting devices/reflectors) has 179,734 citations with only 1.8% OOS rate, and 393.78 (Windshield condition) has 157,894 citations with 0.3% OOS rate. The enforcement pattern is clear: cargo securement defects trigger immediate removal from service, whereas lighting and visibility issues often result in citations without OOS orders.
How to avoid it
If you're assigned a load of boulders or large aggregate stone, complete these steps before departure:
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Inspect the load bed and securement points. Walk the trailer or truck bed and verify that chains, straps, or blocks are present, properly attached to anchor points, and show no visible rust, fraying, or damage. Damaged securement equipment will fail inspection.
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Verify chain or strap tension. Boulders must not shift, roll, or settle during normal braking or turning. Manually tug on the securement to ensure there's no slack. Loose chains are the quickest path to an OOS citation.
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Use appropriate equipment for load weight. Smaller boulders may require different securement than large granite or limestone blocks. If you're uncertain about the correct method, ask your dispatcher or the shipper for documentation of required securement standards.
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Check anchor points on the vehicle. D-rings, stake pockets, and chain hooks must be secure, non-corroded, and capable of holding the rated tension. A missing or broken anchor point means your load isn't properly secured, period.
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Document the securement method. Take photos or note the securement type and configuration on your bill of lading. If questioned by an inspector, you'll have evidence that the load was properly prepared.
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Know your state's specific rules. While federal standards apply nationwide, individual states may have additional requirements for oversized or heavy loads. Illinois, where our single recent citation occurred, may have local guidance on boulder transport.
The bottom line: boulder securement is not optional, and when it fails, the enforcement is swift and absolute. Your pre-trip inspection is your first and most important safety tool.