DOT Inspection
A roadside examination of a commercial vehicle, its driver, or both, conducted to CVSA standards by state and federal enforcement. Every inspection's violations and out-of-service results flow into FMCSA's SMS, where they drive the BASIC percentiles and OOS rates CarrierOk serves for every registered carrier.
Learn moreWhat is DOT Inspection?
A DOT inspection is a roadside or facility examination of a commercial motor vehicle and its driver, conducted by state enforcement agencies and FMCSA personnel following the CVSA North American Standard Inspection Program. Inspections occur at weigh stations, dedicated inspection sites, and traffic stops, and range across eight levels — most commonly Level I (full driver and vehicle), Level II (walk-around), and Level III (driver credentials only). Inspectors check driver items such as CDL validity, medical certificate, hours-of-service records via the ELD, and signs of impairment, and vehicle items such as brakes, tires, lighting, coupling devices, cargo securement, and steering. Each violation found is recorded with a severity weight and uploaded to FMCSA's Motor Carrier Management Information System, where it enters the carrier's 24-month SMS history and moves the relevant BASIC — a brake defect hits Vehicle Maintenance, a logbook violation hits Hours-of-Service Compliance. Violations meeting the CVSA Out-of-Service Criteria immediately sideline the driver or vehicle until corrected, and those OOS events accumulate into the carrier's driver and vehicle OOS rates, which also feed the ISS score that tells inspectors whom to pull in next. CarrierOk indexes inspection counts, violations, OOS events, and the resulting percentiles, updated throughout the day.
Why does dot inspection matter?
Insurance Underwriters
Inspection outcomes are the ground truth beneath every score — a carrier with rising violations per inspection or an OOS rate above the national average is deteriorating in a way loss runs won't show until it's too late.
Freight Brokers
A vehicle placed out of service mid-route means your load sits until the defect is fixed — carriers with high vehicle OOS rates are service risks before they're liability risks.
Developers & Platforms
Combine inspections_total with OOS counts to compute rates client-side, and use oos_alert_driver and oos_alert_vehicle for threshold-crossing flags without maintaining your own national-average baselines.
Key values & thresholds
| Category | Value |
|---|---|
| Standard | CVSA North American Standard |
| Most Thorough | Level I (driver + full vehicle) |
| Data Destination | MCMIS → SMS (24-month window) |
| OOS Consequence | Sidelined until violation corrected |
DOT Inspection in the CarrierOk API
This data is available via the /v2/profile endpoint. The following fields are returned in the carrier profile:
/v2/profileinspections_totalinspections_driver_out_of_serviceinspections_vehicle_out_of_serviceviolations_totaloos_alert_driveroos_alert_vehicleFrequently asked questions
What do inspectors check during a DOT inspection?
It depends on the level. A Level I inspection — the full North American Standard — covers both the driver and the vehicle: CDL and medical certificate, hours-of-service records from the ELD, seat belt use, and signs of impairment on the driver side; brakes, tires, wheels, lighting, steering, suspension, coupling devices, fuel systems, and cargo securement on the vehicle side. Level II covers similar ground without going under the vehicle, and Level III examines only driver credentials and records. Every violation found is recorded and reported to FMCSA regardless of whether a citation is issued.
How do inspection results affect a carrier's safety scores?
Every violation from every inspection enters FMCSA's Safety Measurement System with a severity weight and counts against the relevant BASIC for 24 months, with recent events weighted more heavily. A brake violation raises the Vehicle Maintenance measure; a falsified log raises Hours-of-Service Compliance. Clean inspections help too — they add to the carrier's inspection count, which is the denominator in the peer ranking. Out-of-service violations additionally accumulate into driver and vehicle OOS rates, and the whole picture feeds the ISS score that determines how often the carrier gets inspected next.
What happens if a vehicle or driver is placed out of service?
An out-of-service order means the vehicle cannot move or the driver cannot operate until the disqualifying condition is corrected — a vehicle with failed brakes must be repaired on the spot or towed, and a driver over hours must take the required rest. Violating an OOS order carries heavy fines for both driver and carrier and is itself a serious violation. OOS events are strong risk signals: CarrierOk exposes driver and vehicle OOS counts and alert flags so elevated OOS rates surface in screening before they surface as a stranded load or a claim.
Related terms
BASIC Percentile
A 0-100 peer-relative safety score across seven FMCSA categories: Unsafe Driving, HOS, Vehicle Maintenance, Controlled Substances, Driver Fitness, Hazmat, and Crash Indicator. Higher is worse. CarrierOk computes all 7 BASICs including the two FMCSA withholds from public view.
ISS Score (Inspection Selection System)
FMCSA's composite 1-100 algorithm for prioritizing carriers at roadside inspections. Higher scores mean higher inspection probability. The insurance industry widely uses ISS as a single-number risk indicator because it synthesizes multiple BASIC dimensions. CarrierOk serves ISS scores via the iss_value API field.
OOS Rate (Out-of-Service Rate)
The percentage of a carrier's roadside inspections that result in an out-of-service order, meaning the driver or vehicle is prohibited from operating until the violation is corrected. National average vehicle OOS rate is approximately 21%. CarrierOk provides both driver and vehicle OOS rates and flags carriers exceeding national averages.
SMS (Safety Measurement System)
FMCSA's quantitative system for measuring motor carrier safety performance using inspection, crash, and investigation data. SMS produces the BASIC percentile scores that underpin the CSA enforcement program. CarrierOk computes all 7 BASIC percentiles from SMS source data and updates more frequently than FMCSA's monthly cycle.
CVSA (Commercial Vehicle Safety Alliance)
The nonprofit alliance of US, Canadian, and Mexican enforcement agencies that sets North American roadside inspection standards, including the eight inspection levels and out-of-service criteria. CVSA-standard inspection results feed directly into the SMS data CarrierOk indexes for every registered carrier.
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