Driver and vehicle out-of-service rates explained

During a roadside inspection an officer can place a driver or vehicle out of service (OOS) for serious violations — the truck can't move until the problem is fixed.

How the rate is calculated

The OOS rate is the number of inspections with an OOS order divided by the number of inspections of that type (driver or vehicle) over a period, usually 24 months. FMCSA publishes national averages alongside carrier rates; LoadLookout shows them side by side.

How to read it

• Small samples are noisy — five inspections and one OOS is 20%.
• A vehicle OOS rate well above the national average can point to maintenance problems.
• A high driver OOS rate can point to hours-of-service or licensing issues.

Rates describe past inspections, not future performance.