Full explanation
Out-of-service (OOS) rate is a key safety metric calculated as the percentage of roadside inspections that result in an out-of-service order. The rate is tracked separately for vehicles (mechanical defects) and drivers (qualification/fitness issues). The national average vehicle OOS rate is approximately 21.4%, meaning roughly 1 in 5 trucks inspected are found to have safety violations severe enough to be taken off the road. The national average driver OOS rate is approximately 5.51%. Carriers with OOS rates significantly above these averages are flagged for increased scrutiny, targeted inspections, and potential compliance investigations. OOS rates are a component of FMCSA's BASIC scoring and directly influence Truck Graph's composite risk score (weighted at 30%). A high OOS rate is one of the strongest predictors of future crash involvement, making it a critical metric for shippers and brokers evaluating carrier safety. Truck Graph calculates OOS rates using 5.25 million inspection records with a 24-month rolling window.
Source: FMCSA: Inspection Program
Frequently asked questions
What is a good out-of-service rate?
A vehicle OOS rate below the 21.4% national average is considered acceptable. Top-performing carriers maintain rates below 10%. Rates above 30% indicate systemic maintenance or safety management issues.
How is OOS rate calculated?
OOS Rate = (Number of inspections with OOS violations ÷ Total number of inspections) × 100. Truck Graph uses a 24-month rolling window for this calculation.
Does OOS rate affect carrier authority?
Indirectly. Consistently high OOS rates trigger FMCSA interventions that can escalate to unsatisfactory safety ratings, which lead to authority revocation if not corrected within specific timeframes.
Related terms
A federal enforcement action that immediately prohibits a carrier, vehicle, or d...
BASIC ScoreBehavior Analysis and Safety Improvement Categories — FMCSA's percentile-based s...
Safety RatingAn official FMCSA assessment of a motor carrier's safety management — rated Sati...
Vehicle Maintenance BASICFMCSA safety category measuring carrier compliance with vehicle inspection, repa...