What 393.17A means in plain language
FMCSR 393.17A covers lamps and reflectors that do not meet federal requirements. Your vehicle must have working lights and reflectors in the right locations, brightness levels, and colors to be visible to other drivers—especially at night and in low visibility.
This includes headlamps, tail lamps, clearance lights, turn signals, and retroreflectors (the bright strips on the back and sides of your trailer). If any of these are missing, broken, dim, or the wrong color, you're in violation. It's a straightforward vehicle condition rule: inspectors check that lights work and reflectors are present and visible.
The regulation applies to every commercial motor vehicle operated on public roads. There's no exception for short trips or daylight-only driving—if a lamp or reflector is defective, it counts.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.17A shows up rarely but with real enforcement bite. Our database records 12 all-time citations for this code, with 2 citations in the last 12 months and 0 in the last 90 days.
When inspectors do cite it, they place the vehicle out of service at a 58.3% rate—notably higher than the all-FMCSR average of 31.4%. This means if you're caught, there's better than even odds your truck gets sidelined until the defect is fixed. That's a direct financial hit: downtime, repair costs, missed loads.
Ranked #2132 of 3,036 FMCSR codes by citation volume, 393.17A is uncommon, but its OOS severity tells you inspectors treat it seriously. A broken lamp isn't a nitpick in their eyes—it's a safety hazard that gets trucks off the road.
Who gets cited most
Our inspection data does not provide state-level breakdowns for this code at citation volumes sufficient to rank states. The citations recorded are distributed across multiple small operators, each with one recorded violation.
Among carriers in our database, violations are sparse and spread: J & V Trucking Co Inc, Frank A Adams, FAF LLC, A & J Transport LLC, McCary's Trucking, SS Transports LLC, HB Trans Car LLC, J&K Hauling Services LLC, Platinum Towing and Recovery Inc, and It's A Brighter Day Development LLC each show one citation. This pattern suggests 393.17A is an isolated defect rather than a fleet-wide compliance pattern—when it happens, it usually affects one vehicle at a time.
Vehicle makes cited include Internationals (3 citations), Frieghtliners (2 citations), and single citations for Ford, GMC, Hyundai, Kenworth, and others. No single manufacturer dominates, indicating the issue is driven by maintenance and inspection habits, not design.
How severe is this compared to similar codes
393.17A sits within vehicle maintenance violations, but its enforcement footprint is tiny compared to related codes. For context:
393.9(a) — Inoperable required lamps — has 660,737 all-time citations with a 15.4% OOS rate. That code is roughly 55,000 times more frequently cited than 393.17A, and when it is cited, trucks are sidelined much less often. The difference suggests 393.9(a) captures everyday burned-out bulbs and minor defects, while 393.17A targets more systematic or severe inadequacy.
393.11 — Lighting devices and reflectors — has 179,734 citations and a 1.8% OOS rate. Again, far more common and much less likely to result in out-of-service status.
396.3(a)(1) — Inspection, repair, and maintenance general — shows 236,919 citations at a 45.3% OOS rate. When inspectors cite broad maintenance violations, they ground trucks about as often as they do for 393.17A, suggesting these are companion findings tied to systemic vehicle condition issues.
The rarity of 393.17A combined with its high OOS rate tells you: inspectors don't write this citation often, but when they do, the defect is severe enough to sideline your rig.
How to avoid it
Lamps and reflectors are visible, easy-to-check items. A solid pre-trip will catch almost every defect before an inspector does.
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Do a full walk-around before every shift. Turn on headlamps, high beams, low beams, and all marker lights while standing at the front, sides, and rear of your truck and trailer. Look for burned-out bulbs, cracks in lens covers, and moisture inside light housings. Replace any bulb that's dim or dead.
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Check all retroreflectors on your trailer—front, sides, and rear. These are the bright red and white strips. Make sure they're clean, visible, and not peeling or missing. Mud and road grime cut visibility dramatically; a quick wash or wipe can prevent a citation.
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Inspect wiring and connections. Corrosion, loose wires, and water intrusion cause intermittent and complete lamp failures. Pay special attention to connections near the lights themselves. Tighten any loose plug, and replace corroded sockets.
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Know your vehicle's lighting setup. Different truck and trailer makes have lamps in different locations. Review your owner's manual or talk to your fleet maintenance team so you know what lights should be where and working. This takes five minutes and prevents guessing.
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Don't ignore a warning light or a lamp you know is out. Get it fixed before you go back on the road. A citation is cheap compared to being stranded, failing inspection, and losing revenue.
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Keep spare bulbs and fuses on your truck. Most lamp failures are quick fixes. Carrying spares means you can fix it yourself at a rest area instead of waiting for a shop.
Lamps and reflectors are the easiest safety item on your vehicle to inspect and maintain. A few minutes of pre-trip diligence will keep you out of the 58.3% of drivers who get sidelined for this violation.