Safety Data Methodology & Compliance
A complete, transparent guide explaining how we ingest official US DOT safety records, calculate roadside failure rates, and strictly comply with federal FAST Act regulations.
How US DOT Roadside Safety Records Are Generated
Commercial motor vehicle safety checks take place across interstate highways, weigh stations, border crossings, and rest areas in all 50 US states. Certified state troopers and Commercial Vehicle Safety Alliance (CVSA) certified inspectors examine semi-trucks, trailers, and drivers.
When an officer discovers a safety hazardβsuch as defective air brakes, worn tire tread under 2/32 inch, or an hours-of-service logbook violationβthe finding is recorded on an official inspection report and uploaded to the federal Motor Carrier Management Information System (MCMIS).
If a safety defect exceeds critical North American Standard Out-of-Service Criteria, the truck or driver is placed Out of Service (OOS) and legally prohibited from driving until the defect is repaired. CarrierSafetyData aggregates these records every month to provide crystal-clear visibility into fleet safety records.
The 6 Roadside Inspection Levels Explained
Not all inspections are the same. State enforcement officers conduct 6 distinct inspection levels defined by the Commercial Vehicle Safety Alliance (CVSA).
Level I: North American Standard Inspection
Full 37 StepsThe most thorough inspection. The officer climbs underneath the semi-truck to check brake pushrod stroke, steering lash, suspension, exhaust, frame, and coupling devices, while simultaneously auditing the driver's CDL, medical examiner's certificate, and Electronic Logging Device (ELD) records.
Level II: Walk-Around Driver & Vehicle
Walk-AroundIncludes everything in Level I except the inspector does not crawl under the tractor or trailer. Focuses on visible exterior lighting, tire condition, wheel fasteners, cargo securement, and full driver credential/logbook checks.
Level III: Driver-Only Credential Inspection
Driver FocusStrictly audits driver paperwork without inspecting vehicle hardware. Checks commercial driver license (CDL) endorsements, Medical Examiner's Certificate, Record of Duty Status (RODS/ELD), seatbelt compliance, and Drug & Alcohol Clearinghouse status.
Level IV: Special One-Time Study
Targeted StudyA targeted inspection focusing on a specific vehicle component or regulatory topic, such as a nationwide brake safety week, tire inflation blitz, or cargo tanker pressure valve research.
Level V: Vehicle-Only Inspection
Terminal InspectionConducted on tractors and trailers at carrier yards or terminals without the driver present. Performs the complete Level I mechanical inspection protocol.
Level VI: Radioactive Material Inspection
Hazmat SpecEnhanced inspection specifically for commercial transport of Highway Route Controlled Quantities (HRCQ) of radioactive materials, requiring 100% defect-free equipment before departure.
How Safety Metrics Are Calculated
We use official FMCSA formulas to calculate roadside compliance rates over the trailing 24 months.
Vehicle Out-of-Service Rate Vehicle OOS
Measures how often commercial trucks fail mechanical inspections and are ordered off the road immediately until repaired.
National Benchmark: 21.4%. Fleets with a vehicle OOS rate exceeding 21.4% present higher roadside breakdown and freight delay risk.
Driver Out-of-Service Rate Driver OOS
Measures how often drivers are placed out of service for exceeding legal hours of service, false log entries, or license disqualification.
National Benchmark: 5.5%. A score higher than 5.5% flags potential driver fatigue and compliance concerns.
Hazardous Materials (Hazmat) OOS Hazmat OOS
Tracks placard violations, cargo containment tank defects, and shipping paper non-compliance for dangerous goods transport.
National Benchmark: 4.5%. Hazmat inspections enforce strict federal packaging and containment standards.
24-Month DOT Reportable Crashes Crash Record
Tracks commercial crashes meeting the mandatory federal criteria defined under 49 CFR Part 390.15.
Minor scratches or non-towed fender benders without injuries are excluded from federal DOT crash statistics.
How Time Weighting Affects Roadside Violations
The FMCSA uses a time-decay model so recent roadside violations carry significantly more weight than older ones. A motor carrier that operates safely for consecutive months sees their safety score improve steadily.
Recent violations carry maximum weight. Three times the severity points are applied to the carrier's profile.
Violations between 6 and 12 months fade to two times severity weight as time passes without repeats.
Older violations carry minimal single weight. Once past 24 months, violations automatically drop to 0x and vanish.
FAST Act Section 5223 Compliance Policy
On December 4, 2015, the US Congress enacted the Fixing America's Surface Transportation (FAST) Act (Pub. L. 114-94). Under Section 5223 of the FAST Act, the FMCSA was ordered to remove public display of relative Safety Measurement System (SMS) percentile rankings because of statistical flaws when comparing small carriers against mega-fleets.
CarrierSafetyData strictly complies with all federal transparency and privacy laws:
- β Zero Public Percentile Ranks: We do not publish or calculate restricted relative percentile scores.
- β 100% Factual Public Records: We publish raw, objective inspection counts, verified violation categories, out-of-service rates, and official insurance filings.
- β Fair National Baselines: We compare fleet failure rates against official national averages established by the FMCSA.
This approach gives freight brokers, shippers, and drivers objective, legally compliant safety data to protect their businesses without relying on restricted or flawed ranking models.
Frequently Asked Questions About Methodology
Detailed answers regarding safety calculations, data sources, and federal compliance.
All roadside inspection records and out-of-service rates published on CarrierSafetyData cover a rolling 24-month window. In accordance with FMCSA rules, any inspection or violation older than 24 months automatically drops off a carrier's active profile.
Under Section 5223 of the federal FAST Act (Fixing America's Surface Transportation Act), the US Congress restricted public display of relative SMS percentile scores. We strictly adhere to federal law by publishing only raw, factual public records: exact violation counts, out-of-service percentages, national averages, and active insurance filings.
The Vehicle OOS Rate is calculated as (Total Vehicle Inspections resulting in an OOS Order divided by Total Vehicle Inspections) multiplied by 100. The Driver OOS Rate is calculated as (Total Driver Inspections resulting in an OOS Order divided by Total Driver Inspections) multiplied by 100. These are evaluated over the trailing 24 months and compared against national benchmark averages.
Under 49 CFR Β§ 390.15, a commercial motor vehicle accident is only reportable to the DOT if it results in at least one fatality, bodily injury requiring immediate medical treatment away from the scene, or disabling damage requiring one or more vehicles to be towed from the scene. Minor parking lot scratches or fender benders without towaway or injury are not counted.
The FMCSA weights inspection violations based on age: violations occurring in the last 6 months carry a 3x weight multiplier; violations between 6 and 12 months carry a 2x multiplier; and violations between 12 and 24 months carry a 1x multiplier. Once a violation passes 24 months, it is removed from active scoring.
We cross-reference active Form BMC-91 or BMC-91X primary public liability filings directly from the FMCSA Licensing & Insurance (L&I) database. This confirms whether an interstate carrier maintains the mandatory $750,000 to $5,000,000 policy limit and active BOC-3 process agent filings.
When an inspecting state law enforcement agency approves a DataQ Request for Data Review (RDR), the citation or crash is removed or amended in the federal MCMIS database. Our next monthly sync automatically removes the violation from the carrier's public profile.
