What puts trucks and drivers out of service?
The most frequent out-of-service violations in our indexed FMCSA inspection records, ranked by violation code.
All violation codes
Highest OOS count first. Codes with no recorded OOS occurrences appear last.
| Violation code | Description | OOS occurrences | All occurrences | Share of all OOS |
|---|---|---|---|---|
| 393.207B-AALPME-OOS | More than 25% of the locking pins are missing or not engaged | 4,653 | 4,717 | 0.19% |
| 391.11B4-DEN | Driver operating a CMV without proper endorsements or in violation of restrictions | 4,631 | 4,756 | 0.19% |
| 393.205A | Wheel/rim cracked or broken | 4,575 | 6,174 | 0.19% |
| 393.130B-CHVE | Heavy Vehicles/Equipment - Improper securement of accessory equipment or articulated vehicles | 4,557 | 4,593 | 0.19% |
| 393.207A-SUBL | Suspension - U-bolt, u-bolt bottom plate, or other axle clamp bolt loose/cracked/broken/missing. | 4,538 | 4,808 | 0.19% |
| 393.75A1-TFBMF | Tires - Front, belt material/casing ply showing in tread area | 4,455 | 4,603 | 0.18% |
| 393.205A-WRBH | Wheel/Rim - Cracks between stud holes/hand holes | 4,295 | 4,395 | 0.18% |
| 393.23PT | All required lamps on towed vehicle inoperative due to no electrical connection | 4,268 | 4,575 | 0.18% |
| 393.75G-TFWETL | Tires - Front, weight carried exceeds tire load limit | 4,210 | 4,330 | 0.17% |
| 393.9T | Inoperable tail lamp | 4,208 | 36,708 | 0.17% |
| 393.43A | No/improper tractor protection valve | 3,944 | 4,737 | 0.16% |
| 392.2-LCDLR | Restriction - (CDL) - Operate a CMV in violation of a restriction. | 3,865 | 3,895 | 0.16% |
| 393.48A-BI-SA | Brake - Inoperative on a steering axle | 3,792 | 4,012 | 0.16% |
| 393.75A2 | Tire-tread and/or sidewall separation | 3,680 | 22,550 | 0.15% |
| 393.134 | No/improper securement of roll/hook container | 3,665 | 3,787 | 0.15% |
| 393.75B-TF | Tires - Front, less than 2/32 inch tread depth | 3,618 | 4,229 | 0.15% |
| 393.207F | Air suspension pressure loss | 3,617 | 8,953 | 0.15% |
| 391.11B4-CLHA | Medical (Certificate) - Operating a commercial vehicle without corrective lenses or hearing aid as indicated on the driver's medical certificate | 3,583 | 3,606 | 0.15% |
| 391.41A1-FPC | Operating a property-carrying vehicle without possessing a valid medical certificate. Previously Cited on [DATE] | 3,550 | 3,670 | 0.15% |
| 391.11B5-DNL | Driver does not have a valid operator's license for the CMV being operated | 3,537 | 3,671 | 0.15% |
| 390.3E | Driver prohibited from performing safety sensitive functions per 382.501(a) in the Drug and Alcohol Clearinghouse | 3,498 | 3,556 | 0.15% |
| 383.91A-LCDL | License (CDL) - Operate a CMV without proper CDL class | 3,460 | 3,486 | 0.14% |
| 396.3A1-TFCV | Tires - Front, in contact with a part of the vehicle | 3,426 | 3,468 | 0.14% |
| 393.9A-LSLI | Lighting - Stop lamps - Any inoperative. | 3,395 | 69,203 | 0.14% |
| 393.11A1-LSLMWR | Lighting - Stop lamps - Both missing when required to be on. | 3,377 | 3,459 | 0.14% |
| 391.11B2-S | Driver cannot satisfy the English language proficiency requirements of 391.11(b)(2) in accordance with the current corresponding FMCSA enforcement guidance (391.1 | 3,366 | 3,547 | 0.14% |
| 391.41A-MCPVI | Medical (Certificate) - Operating a passenger-carrying vehicle without a valid medical certificate in possession or on file with the state drivers licensing agenc | 3,343 | 3,536 | 0.14% |
| 393.205C | Wheel fasteners loose and/or missing | 3,289 | 20,586 | 0.14% |
| 393.126B-CIM | Intermodal Containers - Improper securement of intermodal containers transported on container chassis vehicle(s) | 3,277 | 3,337 | 0.14% |
| 393.75C | Tire-other tread depth less than 2/32 of inch measured in a major tread groove | 3,235 | 86,534 | 0.13% |
| 393.47B | Mis-matched brake chambers on same axle | 3,208 | 3,826 | 0.13% |
| 393.201A-FRMC | Frame - Cracked/loose/broken frame member affecting support of functional components | 3,101 | 3,616 | 0.13% |
| 393.45D | Brake connections with leaks or constrictions | 3,078 | 17,435 | 0.13% |
| 393.106D-C | Cargo - Insufficient aggregate working load limit for cargo transported | 3,058 | 3,081 | 0.13% |
| 393.47A-BCFSBD-SA | Drum Brake - Contaminated friction surface on a steering axle | 3,058 | 3,131 | 0.13% |
| 393.45A-BHTIJ | Air Brake - Improperly joined such as a splice made by sliding the hose ends over a piece of tubing and clamping the hose to the tube | 3,047 | 3,106 | 0.13% |
| 383.51A-LCDLRSWD | License (CDL) - A person required to have a CLP or CDL who is disqualified must not drive a CMV | 3,001 | 3,911 | 0.12% |
| 393.75C-OOS | Tire-other tread depth less than 1/32 of inch measured in 2 adjacent major tread grooves 3 separate locations 8 inches apart | 2,970 | 4,731 | 0.12% |
| 393.209D-STBSP | Steering - Ball and socket joint has movement greater than 1/8 inch measured with hand pressure | 2,808 | 2,964 | 0.12% |
| 396.3A1-LLEAK | A liquid fuel system with a dripping leak at any point | 2,775 | 2,844 | 0.12% |
| 396.3A1-BARS | Air Brake - Air reservoir separated from its original attachment points or moving more than 1 inch | 2,722 | 3,953 | 0.11% |
| 396.5B-HLOW | Hubs - oil and/or Grease Leaking from hub - outer wheel | 2,691 | 9,481 | 0.11% |
| 395.8E1PC-OOS | HOS - False record of duty status that concealed an HOS limitation violation after the last rest period. Driver improperly used Personal Conveyance | 2,667 | 5,040 | 0.11% |
| 396.3A1-HC | Hubs - Hub cap missing or broken | 2,667 | 2,990 | 0.11% |
| 383.51A-SOUT | Driving a CMV while CDL is suspended for safety-related or unknown reason and outside the state of driver's license issuance | 2,649 | 2,666 | 0.11% |
| 393.207C | Leaf spring assembly defective/missing | 2,646 | 4,209 | 0.11% |
| 396.3A1-BNMH | Brake - Non-manufactured hole or crack in the spring brake housing section of a parking brake | 2,624 | 2,660 | 0.11% |
| 393.207B | Adjustable axle locking pins missing or not engaged | 2,599 | 4,824 | 0.11% |
| 392.2-SLLSOA | State/Local Laws - State operating authority violation | 2,595 | 32,721 | 0.11% |
| 392.9A1 | Failing to secure cargo as specified in 49 CFR 393.100 through 393.142 | 2,595 | 2,973 | 0.11% |
How to read this report
Each indexed violation identity counts once. Only a violation explicitly marked out of service contributes to the OOS count. Repeated copies are counted once; conflicting code or OOS values are excluded. Unknown flags remain in all occurrences but not in the OOS count. Missing codes appear as “Code not reported”.
These are violation counts, not unique inspections, trucks, drivers, or carrier-wide out-of-service orders. Coverage describes the currently indexed inspection dataset, not all historical FMCSA records. Frequencies do not establish crash causation or a carrier’s safety rating.
Unknown OOS flags: 112 · Conflicting records excluded: 0
FMCSA source data ↗