What 393.136D means in plain language
FMCSR 393.136D addresses the securement of cubic boulders on your vehicle. When you're hauling large stone or aggregate material in boulder form, federal regulations require that these loads be properly secured so they cannot shift, roll, or fall during transport.
A citation for this code means an inspector found that cubic boulders on your trailer were not adequately restrained or tied down. This could involve loose straps, missing tie-downs, improper placement within the cargo area, or failure to use appropriate blocking or bracing to prevent movement. The regulation exists because unsecured loads—especially heavy materials like boulders—pose a serious risk to following vehicles and can cause accidents if they break free on the road.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, 393.136D is cited infrequently but with exceptional severity. We have recorded 8 all-time citations for this violation. In the last 12 months, there were 4 citations, and 3 in the past 90 days.
What stands out: every single citation for 393.136D has resulted in an out-of-service placement—a 100% OOS rate. This is dramatically higher than the all-FMCSR average of 31.4%, making this one of the most consistently serious violations we track. When an inspector cites this code, your vehicle does not pass inspection and cannot legally operate until the violation is corrected.
393.136D ranks #2269 out of 3,036 FMCSR codes by citation volume, reflecting its rarity. But the 100% enforcement-to-OOS ratio tells you that when it does occur, regulators treat it as a critical safety defect.
Who gets cited most
Our data shows Texas accounts for 4 citations over the last 180 days, with a 100% OOS rate. Because the total citation count for this code is very low nationally, geographic concentration is limited, and most other states have zero or near-zero enforcement activity.
No single carrier appears with a pattern of repeat citations. Our database shows eight different carriers with one citation each across all-time records, indicating this violation is distributed across the industry rather than concentrated in specific fleets.
How severe is this compared to similar codes
To understand the severity context, compare 393.136D to other vehicle maintenance codes:
- 393.9(a) (Inoperable required lamps): 660,737 citations with a 15.4% OOS rate. This is far more frequent but much less likely to trigger an out-of-service order.
- 396.3(a)(1) (Inspection/repair/maintenance - general): 236,919 citations with a 45.3% OOS rate. Still more common, with a higher-than-average OOS rate, but well below 393.136D's 100%.
- 393.78 (Windshield condition defective): 157,894 citations with a 0.3% OOS rate. Despite high citation volume, almost never results in OOS placement.
The gap between 393.136D's enforcement behavior and that of comparable maintenance violations underscores how seriously DOT/CVSA inspectors view cargo securement failures, particularly with heavy materials.
How to avoid it
Based on patterns in our inspection data, the following pre-trip actions will reduce your risk:
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Inspect all cargo tie-downs and straps before leaving the yard. Check that every strap is tight, properly threaded through anchor points, and shows no signs of fraying or damage. If you're hauling boulders or aggregate, verify that each tie-down has adequate tension to prevent any shifting.
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Verify proper load placement and blocking. Boulders should be positioned securely within the trailer bed. Use appropriate blocking, bracing, or dunnage to prevent movement side-to-side or lengthwise. Do not assume gravity alone will hold a heavy load in place.
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Address brake and suspension issues early. Our data shows that 393.47E (slack adjuster defective), 393.45B2UV (brake tubing/hoses inadequate), and 393.207A (suspension defective) commonly appear alongside 393.136D violations. A truck with soft brakes or a sagging suspension is more prone to load shift during braking or cornering. Perform pre-trip brake checks and confirm your suspension is level.
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Check steering and coupling integrity. Co-occurring citations include 393.53B (steering system components worn) and 393.55D1/E (coupling device defects). A loose steering system or poor coupling alignment can cause trailer sway, which places extra stress on cargo securement. Ensure your steering feels responsive and your trailer tracks straight.
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Secure lighting and marking on projecting loads. If your boulders extend beyond the trailer dimensions, they must be marked and lit per 393.24A requirements. Proper marking also signals to inspectors that you're aware of your load profile.
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Document your pre-trip inspection. Keep notes on tie-down condition, load security checks, and any adjustments you made. If cited, this record demonstrates due diligence and helps with appeals or future compliance discussions with your fleet.