What 393.136B means in plain language
FMCSR 393.136B addresses the proper placement and positioning of boulders on a commercial vehicle. When an inspector cites this code, they are documenting that a boulder or large rock being transported is not secured or positioned in compliance with federal motor carrier safety standards.
This regulation applies to vehicles hauling aggregate materials, landscaping stone, or similar cargo that includes boulders or large stone pieces. The rule ensures that such cargo is arranged and restrained in a way that prevents it from shifting, rolling, or falling during transit—which could damage the vehicle, other traffic, or cause an accident.
If you received this citation, the inspector determined that your boulder cargo did not meet the federal standard for placement or positioning at the time of inspection.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.136B is an extremely uncommon citation. We have documented 2 all-time citations for this code, with 1 citation occurring in the last 12 months and 0 in the last 90 days.
What makes this code notable is its out-of-service rate: 100.0%. Both vehicles cited for 393.136B were placed out of service. This is substantially higher than the all-FMCSR average OOS rate of 31.4%, indicating that when inspectors cite this violation, they typically judge the cargo positioning hazardous enough to remove the vehicle from service immediately.
Nationally, 393.136B ranks 2,651st out of 3,036 FMCSR codes by citation volume, placing it among the rarest violations in the federal inspection database.
Who gets cited most
Our inspection records show that Illinois has the only documented citation for this code in the last 180 days—1 citation with a 100.0% out-of-service rate.
Because of the extremely low citation volume, historical data shows only two carriers with any record of this violation: Workhorse Trucking LLC (USDOT 2929803) with 1 citation, and Mirela's Company Inc (USDOT 3176429) with 1 citation. The rarity of these citations means that enforcement patterns are not yet robust enough to identify carrier-specific trends.
Vehicles cited include various makes: Kenworth, Smith, Trailer, and Volvo. No single make dominates the violation history.
How severe is this compared to similar codes
Comparing 393.136B to other vehicle maintenance codes shows how rarely this violation occurs in enforcement:
- 393.9(a) — Inoperable required lamps: 660,737 citations with 15.4% OOS rate. Lamp defects are among the most common vehicle maintenance violations, but are placed out of service far less frequently than 393.136B.
- 396.3(a)(1) — Inspection/repair/maintenance - general: 236,919 citations with 45.3% OOS rate. General maintenance failures are cited frequently and result in OOS placement at a rate between the all-code average and 393.136B.
- 393.47E — Slack adjuster defective: 180,363 citations with 0.0% OOS rate. Brake-related defects are common but typically do not result in immediate out-of-service placement, unlike the 100% OOS rate seen with boulder placement violations.
The 100.0% out-of-service rate for 393.136B reflects that inspectors view improper boulder positioning as an immediate safety hazard requiring vehicle removal from service before transport can resume.
How to avoid it
If you haul stone, aggregate, or boulder-type cargo, take these steps to prevent a 393.136B citation:
- Pre-trip cargo inspection: Before loading, verify that all boulders or large stone pieces fit within the vehicle's cargo bed or flatbed boundaries. Check that no cargo extends beyond the sides, front, or rear of the vehicle beyond permitted overhang limits.
- Secure large pieces properly: Ensure boulders are not loose or free-rolling in the cargo area. Use straps, chains, or cargo locks rated for the weight and dimensions of each stone. Do not rely on adjacent pieces to hold one in place.
- Level and distribute load: Position boulders so the load is balanced across the vehicle's width and length. Avoid stacking boulders in a way that creates an unstable pyramid or arrangement that could shift during braking or turning.
- Check for shifting en route: During a pre-trip walk-around, visually confirm that no cargo has moved since loading. Look for gaps between boulders that were not present at loading, or stones that have rotated.
- Know your vehicle's capacity: Understand the rated load capacity and cargo bed dimensions of your specific truck or trailer. Overloading or forcing oversized boulders into undersized spaces creates positioning violations.
- Document your load: Take photos of the loaded cargo arrangement before departing. This creates a reference if any question arises about how the cargo was initially positioned.
The 100% out-of-service rate associated with this violation means that proper placement is not a minor adjustment—it is a critical safety requirement that inspectors enforce strictly.