What 393.9B-LPLOWR means in plain language
When your truck carries a load that projects beyond the normal cargo area—whether that's pipe, lumber, machinery, or oversized equipment—federal safety rules require you to mark it with lighting. If you're hauling such a load and an inspector finds that any of those required lights is blocked, covered, or not functioning when it should be illuminated, you've violated 393.9B-LPLOWR.
The rule exists because projecting loads create a hazard that other drivers need to see, especially at night or in low visibility. A lamp on the load itself serves as a warning. When that lamp is obscured—whether by tarps, straps, dirt accumulation, or positioning—other road users lose critical visibility cues. The citation means an inspector determined you were required to have certain lights active on or marking that projection, and at least one of them was blocked or invisible when the inspection occurred.
This is a maintenance and compliance issue, not an equipment defect in the traditional sense. You may have functioning lamps, but their placement or coverage renders them ineffective.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.9B-LPLOWR ranks #1717 of 3,036 FMCSR codes by citation volume. We've recorded 37 all-time citations for this violation, with 20 in the last 12 months and 5 in the last 90 days.
Here's what makes this code notable: the out-of-service rate is 94.6%—meaning 35 of 37 drivers cited for this violation were placed out of service on the spot. Compare that to the all-FMCSR average OOS rate of 31.4%. This code triggers OOS decisions at roughly three times the average rate. That's a strong signal that inspectors view obscured load lights as a serious enough defect to pull you from service immediately.
The recent 12-month trend shows consistent but low overall volume: 2 citations in June 2025, 2 in July, then a spike to 5 in September, 4 in October, 2 in December, 1 in January, and 4 in March 2026. The variation month to month is modest, but the OOS placement rate remains extreme—4 OOS out of 5 inspections in September, 4 out of 4 in October, 4 out of 4 in March.
Who gets cited most
Our inspection records show citations for 393.9B-LPLOWR concentrated in a few states over the last 180 days. Tennessee led with 2 citations (both resulting in OOS at 100%), followed by single citations in Georgia, Massachusetts, Michigan, Nevada, Ohio, Florida, and Washington. Each of those states showed a 100% OOS rate.
Carrier names in our data for this code include Murphy Bros Trucking & Construction LLC, WTI Transport LLC, and Rolando Villanueva Navarro—each with one citation. The pattern shows this violation is scattered across many carriers and owner-operators rather than concentrated in one fleet or company type.
Looking at vehicle makes, the data reflects a mix of equipment: 9 unpublished makes, 8 Dodge units, 7 Kenworth trucks, 3 Peterbilt units, and smaller counts of Freightliner, trailers, and custom equipment. The violation appears across various vehicle classes and manufacturers, suggesting it's a behavior and load-securing practice issue rather than a specific equipment design problem.
How severe is this compared to similar codes
To put 393.9B-LPLOWR in context, we compared it to related lighting and maintenance codes in our database. The peer codes in the Vehicle Maintenance category show a wide range of enforcement intensity and OOS outcomes:
393.9(a)—Inoperable required lamps has far higher citation volume at 660,737 all-time citations but a much lower OOS rate of 15.4%. That code covers lamps that don't work at all; inspectors treat those less severely than actively obscured load markers.
393.11—Lighting devices/reflectors accumulated 179,734 citations with only a 1.8% OOS rate, suggesting inspectors use that code for minor lighting issues.
396.3(a)(1)—Inspection/repair/maintenance general shows 236,919 citations and a 45.3% OOS rate, which is substantial but still lower than 393.9B-LPLOWR's 94.6%.
The high OOS rate on 393.9B-LPLOWR relative to its peers indicates inspectors treat obscured load lights as an acute safety concern—arguably more hazardous than a non-functional lamp on the truck itself, because the load projection is the object that actually needs marking.
How to avoid it
If you haul projecting loads, protect yourself and keep your vehicle in service with these concrete steps:
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Inspect lighting before securing the load. Walk around the entire truck and trailer. Identify all required lamps—on the vehicle and any markers required for the load itself. Make sure each is clean, functional, and will remain visible once you secure the cargo.
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Use transparent or non-obstructing tarps and straps. When covering or securing a projecting load, avoid draping tarps, tie-downs, or lumber directly over required lamps. Route straps around lights, not over them. Use mesh tarps if full coverage is needed so light can penetrate.
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Verify clearance before departure. Once the load is on and secured, do a final walk-around in the lighting conditions you'll drive in. If a lamp is hard to see from 100 feet away, it's probably obscured from an inspector's view.
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Check lights during a pre-trip inspection. Our data shows that operating while fatigued or ill co-occurs with this code in multiple inspections. A thorough pre-trip when you're alert catches obscured lights before you leave the yard. Don't skip this step when you're tired.
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Know what loads require lighting. Not every projection needs a lamp, but standards loads (pipe, steel, bridge beams, machinery) typically do. Verify with your dispatch or shipper which lights are mandated for your specific load before you leave.
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Use reflective tape as backup. In addition to functional lamps, apply high-visibility reflective tape to edges of projecting loads. This doesn't replace required lamps, but it provides visual backup and signals to inspectors that you're taking load marking seriously.
The 94.6% OOS rate on this code means getting cited almost guarantees you'll be taken out of service. That means lost hours, potential missed delivery windows, and a mark on your safety record. The violation is entirely preventable with a five-minute pre-trip inspection and thoughtful load securing.