Out-of-Service Violations: Which Ones Get Drivers Parked on the Side of the Road

Out-of-service orders are the most immediate enforcement consequence in trucking. They don't require a hearing, a penalty notice, or a compliance review — an officer at roadside can issue one on the spot. Understanding what triggers them is the most direct path to avoiding them.

What the Regulation Actually Requires

Vehicle OOS criteria are primarily governed by 49 CFR Part 393 (parts and accessories) and 49 CFR Part 395 (HOS). The specific OOS thresholds used by roadside inspectors are published in the CVSA Out-of-Service Criteria, which the Commercial Vehicle Safety Alliance updates annually. FMCSA adopts the CVSA criteria by reference.

When an OOS order is issued, the following applies:

• A driver OOS order prohibits that driver from operating any commercial motor vehicle — but another qualified driver may be able to move the vehicle
• A vehicle OOS order prohibits operation of that specific vehicle — the vehicle cannot move until the OOS condition is corrected and the officer lifts the order or another designated process is followed
• Operating under an OOS order is a separate, more serious violation than the original violation that triggered the OOS — civil penalties are substantially higher
• OOS violations are recorded in FMCSA's MCMIS and immediately affect the carrier's CSA BASIC scores, typically carrying the highest severity weights in their respective BASIC categories

Step-by-Step Practical Breakdown

Driver OOS vs. Vehicle OOS: Different Problems

A driver OOS is a problem with the driver — expired medical card, HOS violations, impairment, CDL issues. The vehicle may still be moved by another qualified, rested driver. Arranging a replacement driver is the carrier's responsibility.

A vehicle OOS is a problem with the equipment — brakes, tires, lights, structural defects. The vehicle cannot move until the defect is repaired and the OOS condition is corrected. Repair must happen at or near the inspection location, or the vehicle may need to be towed. Moving an OOS vehicle without proper repair is a federal violation.

What to Do When an OOS Order Is Issued

1. Do not argue at the scene. Comply with the order. The place to contest an incorrect OOS citation is through the DataQs system after the fact, not in a roadside confrontation.
2. Document everything immediately. Take photos of the defect noted (or the absence of a defect if you believe the citation is incorrect). Note the officer's name, badge number, and the exact violation cited.
3. Notify your carrier immediately — or if you are the carrier, activate your contingency plan. Arrange a replacement driver for a driver OOS; arrange repair for a vehicle OOS.
4. For vehicle OOS: The repair must be performed before the vehicle moves. If roadside repair is not possible, the vehicle must be towed — not driven — to a repair facility. The towing must be arranged with the officer's approval.
5. After repair: Some OOS orders require the officer to inspect and clear the vehicle before it can resume operation. Others allow the driver to self-certify the repair. Know which applies before assuming the vehicle is clear.
6. Challenge incorrect citations through DataQs within 90 days. OOS violations carry heavy CSA weight — even a single successful DataQs challenge can meaningfully improve a BASIC score.

OOS Violations and CSA Scores

OOS conditions carry the highest severity weights in the FMCSA Safety Measurement System — typically a 10 out of 10. A single OOS violation in the Unsafe Driving or Vehicle Maintenance BASIC can move a carrier's percentile significantly, particularly for smaller carriers with limited inspection exposure. See our CSA score guide for how percentiles are calculated.

What Inspectors Actually Look For

Brakes: Brake adjustment is the most common vehicle OOS violation. CVSA brake OOS criteria specify exact stroke limits by brake type and size. Officers measure with gauges — there is no eyeballing. Carriers who skip brake checks between annual inspections consistently appear on officer OOS lists.

ELD and HOS: A driver who cannot produce required logs or whose ELD shows HOS violations faces driver OOS. Officers are trained to look for HOS patterns — driving time that starts immediately after showing 10 hours off, logs that don't match the route, or devices that cannot transfer data.

Tires: Front steer tires are checked with a tread depth gauge. Under 4/32 inch on a front tire is automatic OOS. Drive and trailer tires under 2/32 inch are also OOS. Visible fabric cords or structural damage are OOS regardless of tread depth.

Medical certificates: An expired medical card is an automatic driver OOS. Officers check expiration date and self-certification status in the CDL record. If the card in the DQF doesn't match the CDL record, both documents are suspect.

CDL violations: An endorsement that doesn't cover the load being hauled — hauling hazmat without H endorsement, operating a double/triple without T endorsement — is OOS. The driver is out of service for the specific vehicle and load, not necessarily for all operations.

Impairment indicators: Officers are trained in behavioral indicators of alcohol and drug use. Any observable indicator — smell, slurred speech, dilated pupils, erratic behavior — can trigger a reasonable suspicion evaluation on the spot.