What 393.17(d) means in plain language
FMCSR 393.17(d) addresses the lighting and reflective devices on your commercial motor vehicle. The regulation requires that all lamps and reflectors meet specific federal standards for brightness, color, placement, and function. This includes headlamps, taillamps, clearance lights, marker lights, reflectors, and any other lighting equipment required by FMCSR Part 393.
When an inspector cites you for 393.17(d), they are saying that one or more of these devices do not meet the federal requirements. This might mean a lamp is cracked, dim, missing, the wrong color, or not functioning properly. It could also mean a reflector is damaged, faded, or not installed correctly. The violation focuses on the condition and compliance of the lighting devices themselves, not on your failure to have them inspected or documented.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.17(d) has generated only 36 all-time citations, with zero citations in the last 12 months and zero in the last 90 days. This makes 393.17(d) the least-cited violation in this enforcement snapshot, ranking #1727 of 3,036 FMCSR codes by citation volume.
Most importantly, none of the 36 historical citations resulted in an out-of-service order. The OOS rate for 393.17(d) is 0.0%, meaning inspectors consistently allowed drivers to continue operating after citing this code. This is significantly lower than the all-FMCSR average OOS rate of 31.4%, indicating that enforcement for inadequate lamps and reflectors is treated as a correctable defect rather than an immediate safety threat to vehicle operation.
Who gets cited most
Our data shows fleets such as OBY GLENN MELVIN with 2 citations across all time. The remaining citations are distributed among smaller carriers and owner-operators, each with single citations. Given the very low overall volume of 36 citations, no clear geographic or carrier pattern emerges. The citation distribution suggests that 393.17(d) enforcement is sporadic and not concentrated among specific fleets or regions.
How severe is this compared to similar codes
393.17(d) sits within the Vehicle Maintenance category alongside several higher-volume violations. For comparison, FMCSR 393.9(a)—Inoperable required lamps—has generated 660,737 citations with a 15.4% OOS rate, making it far more frequently cited and more likely to result in immediate removal from service. Another peer code, 393.11—Lighting devices/reflectors—has accumulated 179,734 citations with a 1.8% OOS rate, also substantially higher citation volume than 393.17(d).
The massive gap in citation frequency between 393.17(d) and related codes suggests that inspectors more commonly cite violations that involve completely inoperable or missing lamps (393.9(a)) rather than those that fall under the broader "inadequate" category of 393.17(d). When 393.17(d) is cited, the 0.0% OOS rate indicates it is treated as a maintenance item to correct before the next operation, not an emergency defect.
How to avoid it
Preventing a 393.17(d) citation starts with a thorough pre-trip inspection of all lighting and reflective equipment:
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Check every lamp and reflector: Walk around your vehicle before each trip. Look for cracks, missing lenses, discoloration, or loose connections on headlamps, taillamps, clearance lights, marker lights, and side reflectors. Test each lamp by turning on the vehicle's lights and confirming they illuminate properly.
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Verify color and brightness: Federal requirements specify that headlamps must be white or amber, taillamps and brake lights must be red, and clearance/marker lights must match their designated color. If a lamp appears dim, yellow, or the wrong color, it likely needs replacement or repair.
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Inspect reflectors for fading and damage: Reflectors must be clean and reflective. Dirt, fading, or physical damage reduces their effectiveness. Wipe them clean during your pre-trip; if they no longer reflect light brightly, they need replacement.
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Ensure proper installation: All lighting devices must be securely mounted in their correct locations. If you see a lamp hanging loose, a reflector shifted out of position, or equipment missing entirely, repair or replace it immediately.
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Document any repairs: Keep records of lamp and reflector maintenance and replacement. A well-maintained vehicle is less likely to be cited for inadequate lighting equipment.
Our inspection data shows that Freightliner vehicles account for the highest number of 393.17(d) citations (18), followed by International (6). If you operate one of these makes, pay extra attention to the specific lighting configurations on your model, as they may be more prone to inspector scrutiny or have design features that require closer attention during pre-trip checks.