Glossary
Roadside inspection (levels 1 to 6)
A roadside inspection is a structured examination of a commercial vehicle and/or its driver, conducted by state and federal enforcement at weigh stations, roadside stops, and terminals. Every inspection, clean or not, becomes a public record naming the date, location, level, violations found, and whether the vehicle or driver was placed out of service.
The levels
- Level I: full inspection of driver and vehicle, the most thorough and most common deep check.
- Level II: walk-around driver and vehicle inspection.
- Level III: driver-only (credentials, hours of service, records).
- Level IV: special, typically a one-time study examination.
- Level V: vehicle-only, without the driver present.
- Level VI: enhanced inspection for certain radioactive shipments.
Why inspections carry so much weight in vetting
Inspections are the densest evidence the public record has: millions per year, accumulating for every operating carrier whether or not FMCSA ever audits it. They power the out-of-service rates, the CSA inputs, and several fleetfax derivations the raw record doesn't state directly: which equipment a carrier actually runs, where it actually operates, and whether its inspection cadence just went quiet. Volume matters too: a fleet of any size that is genuinely operating gets inspected eventually, so a claimed fleet with no inspection trail is its own signal.
Related terms
Out-of-service (OOS) rate
The percentage of a carrier's roadside inspections that ended with the vehicle or driver ordered off the road. Compared against published national averages, it's a core inspection-failure metric.
CSA & the BASICs
FMCSA's safety scoring system: seven behavior categories. Official percentiles are hidden from the public for all seven; the raw data behind five of them is public.
Power units
The self-propelled vehicles a carrier reports operating: trucks and truck tractors, not trailers. The fleet-size figure on the federal record, self-reported on the MCS-150.
fleetfax reads public FMCSA data and is not affiliated with FMCSA or the U.S. Department of Transportation. This page explains terminology; it is not legal advice.