Federal Motor Carrier Safety Administration (FMCSA) roadside inspections are examinations of commercial motor vehicles (CMVs) and drivers by Motor Carrier Safety Assistance Program (MCSAP) inspectors. MCSAP inspectors conduct roadside inspections on CMVs and drivers to check that they are in compliance with the Federal Motor Carrier Safety Regulations and Hazardous Materials Regulations.
If an inspection results in a serious violation, the driver is issued an out-of-service (OOS) order. These violations must be corrected before the driver or vehicle can return to service. The FMCSA keeps a close eye on the most common vehicle violations. This data can be used to maintain a safe fleet and keep businesses in compliance with the rules of the road. Here are the 10 most common OOS orders issued for vehicle violations during the 2025 fiscal year.
| Description of Violation | Violation Code | Number of OOS Orders |
| 1. Tires – All others, leaking or inflation less than 50% of the maximum inflation pressure. | 393.75A3-TAOL | 93,806 |
| 2. Brake – Defective brake(s) are equal to or greater than 20% of the service brakes on the vehicle/combination. | 396.3(a)1BOS | 59,133 |
| 3. Lighting – Turn signal – Any inoperative on the rearmost vehicle. | 393.9A-LTSI | 36,619 |
| 4. Tire-flat and/or audible air leak | 393.75(a)(3) | 28,329 |
| 5. Lighting – Stop lamps – Both inoperative when required to be on. | 393.9A-LSLIWR | 24,516 |
| 6. Air Brake – Hose/tubing damage extending through the outer reinforcement ply. | 393.45B2-BHTD | 21,435 |
| 7. Brake – Breakaway not attached to the towing vehicle. | 393.43DBMA | 19,290 |
| 8. Cargo – Cargo not secured to prevent leaking/spilling/blowing/falling from CMV. | 393.100B-C | 16,830 |
| 9. Inoperative turn signal | 393.9TS | 13,970 |
| 10. Brake – Missing or inoperable breakaway braking system on a trailer(s) or converter dolly. | 393.43D-B | 13,810 |
For a copy of this notice, click here: The 10 Most Common FMCSA Vehicle Violations in the 2025 Fiscal Year