What 393.17B2-LDIL means in plain language
This citation means an inspector found that your commercial motor vehicle's lamps or reflectors do not meet federal requirements. This could be burned-out bulbs, missing reflectors, damaged lens covers, or lamps that are physically misaligned or non-functional.
The regulation requires that all required lighting and reflective devices on your vehicle work properly and remain visible. This applies to headlamps, taillamps, clearance lights, marker lights, reflectors, and any other lighting system mandated by the FMCSR for your vehicle class.
Unlike some violations that get you immediately pulled out of service, this one almost never does. Across our 13 million inspection records, 393.17B2-LDIL has resulted in zero out-of-service orders. The inspector documents the defect, and you correct it—typically a straightforward repair.
What our enforcement data actually shows
Our inspection records show 176 all-time citations for this code, with 111 issued in the last 12 months and 21 in the last 90 days. This places 393.17B2-LDIL at #1249 out of 3,036 FMCSR codes by citation volume—a relatively low-frequency violation.
The 0.0% out-of-service rate stands in sharp contrast to the all-FMCSR average of 31.4%. This is because lamp and reflector defects are typically fixable on the spot or shortly thereafter without rendering the vehicle unsafe for limited operation. None of the 176 citations in our database resulted in an out-of-service order.
Monthly trends over the last 12 months show steady enforcement. Citations ranged from a low of 6 in April 2025 to a high of 13 in June 2025, averaging around 9 per month. This steady pattern suggests inspectors are catching these defects consistently but they are not a widespread epidemic.
Who gets cited most
Across the last 180 days, Maryland leads with 20 citations, followed by Florida and California, each with 6 citations. Pennsylvania, Oklahoma, Georgia, Minnesota, New York, Washington, and Arizona round out the top 10, ranging from 1 to 4 citations each. All of these states maintain a 0.0% out-of-service rate for this code.
Our data shows fleets such as HWS LLC with 5 all-time citations and SILVER SPRING TOWING & RECOVERY LLC with 4 citations have encountered this violation. Neither pattern suggests systemic negligence; rather, they reflect the sheer volume of inspections these carriers operate under.
Vehicle-wise, FORD leads with 22 citations, followed by DODGE (18) and FREIGHTLIN (16). PETERBILT, RAM, INTERNATIO, and HINO all appear in the top 10 as well. This distribution roughly mirrors the prevalence of these makes on American roads, not a specific vulnerability of any single manufacturer.
How severe is this compared to similar codes
In the vehicle maintenance category, 393.17B2-LDIL sits far below the most heavily cited lamp code. FMCSR 393.9(a)—Inoperable required lamps—has logged 660,737 citations with a 15.4% out-of-service rate, making it one of the most-enforced codes overall.
Another peer code, 393.11 (Lighting devices/reflectors), has 179,734 citations with only a 1.8% out-of-service rate. This suggests that most lamp and reflector defects are handled as correctable violations rather than safety-critical roadside removals.
For comparison, 396.3(a)(1)—Inspection/repair/maintenance general—logs 236,919 citations with a 45.3% out-of-service rate, underscoring that broader maintenance failures are treated much more severely. Your 393.17B2-LDIL citation is among the gentler enforcement outcomes in the maintenance category.
How to avoid it
Perform a thorough pre-trip lighting inspection every time you go out:
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Walk the entire vehicle perimeter at dusk or in dim light. Check every headlamp, taillight, marker light, and reflector. Activate your brakes to confirm rear lamps illuminate. Use your hazard flashers to verify that work. A flashlight or phone light helps you spot burned-out bulbs and cracked lenses.
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Inspect lens condition closely. Cracked, fogged, or heavily soiled lens covers can fail inspection even if the bulb works. Clean lenses with a soft cloth; replace any that are visibly damaged. This is especially important after winter road salt exposure or heavy dust conditions.
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Check reflector mounting and visibility. Reflectors must be clean, unobstructed, and firmly mounted. Dirt, road grime, or loose fasteners are easy catches for inspectors. A quick wipe-down takes seconds.
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Replace burned-out bulbs immediately. Don't defer a single bulb or marker light replacement. Our data shows lamps and reflectors co-occur frequently with other lighting-related citations (393.17A1-LSLDMWR and 393.17B2-LDCL each appeared in 9 shared inspections in the last 90 days), suggesting that when one light system begins to fail, others often follow. Staying ahead prevents cascade failures.
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Address brake and coupling system defects early. Fifth wheel defects (393.71H10-CDDSDM) co-occurred in 5 shared inspections with lamp violations in the last 90 days, hinting that trucks with broader mechanical wear are more likely to have lighting issues. A comprehensive pre-trip catch these together.
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If your truck is older or has high mileage, budget for wiring and connector checks. Corroded connectors, loose grounds, and aging wiring harnesses cause intermittent lighting failures. FORD, DODGE, and FREIGHTLIN trucks appear frequently in our data; these models benefit from preventive electrical inspection.