Executive Summary
FMCSA describes SMS as a workload prioritization tool that uses inspections, crashes, and investigation findings to identify carriers for intervention.
SMS compares carriers with similar numbers of safety events. The percentile is relative to that group and is shaped by recency, severity, exposure, and data sufficiency.
Version 3.21, revised in May 2026 and documented in June 2026, added nineteen violations and updated eleven descriptions.
SMS is a prioritization model
The seven BASICs are Unsafe Driving, Crash Indicator, Hours-of-Service Compliance, Vehicle Maintenance, Controlled Substances or Alcohol, Hazardous Materials Compliance, and Driver Fitness. FMCSA combines on-road performance with recent acute and critical investigation violations.
This is a regulatory workload model. It helps direct limited enforcement resources. A freight team can use it as one risk signal, but should not rename it a safety score or claim that it predicts an individual load.
EvidenceSafety Measurement System Methodology: BASIC Prioritization Status, Version 3.21
Recency changes the weight
For applicable inspections and violations, SMS generally uses a twenty-four-month window. Events in the newest six months receive a time weight of three. Events older than six months through twelve months receive two. Events older than twelve months through twenty-four months receive one.
That makes a recent pattern more important than the same pattern aging out. It also means a carrier's profile can improve without a new inspection if older events lose weight. Read the event dates, not only the current percentile.
| Event age | Time weight | Operational reading |
|---|---|---|
| Zero to six months | 3 | Current control issue or current improvement evidence |
| Over six to twelve months | 2 | Still material, but less current |
| Over twelve to twenty-four months | 1 | Historical context approaching the edge of the window |
| Older than twenty-four months | Not in the standard on-road calculation | Useful history, not current SMS weight |
EvidenceSafety Measurement System Methodology: BASIC Prioritization Status, Version 3.21
The denominator decides whether the number is stable
SMS uses safety event groups so carriers are compared with others that have similar numbers of relevant inspections, violations, or crashes. Several BASICs also use power units, vehicle miles traveled, or utilization adjustments.
A carrier with little inspection history can have no percentile or a volatile one. A carrier with many clean inspections may have a better-supported view. Before reacting to a percentile, read the inspection count, violation count, out-of-service count, fleet size, mileage freshness, and event dates.
- Ask how many relevant inspections support the measure.
- Check whether the MCS-150 mileage and power unit data are current.
- Separate driver, vehicle, hours, and hazardous materials issues.
- Look for repeated categories, not only the loudest single violation.
- Treat no percentile as insufficient public evidence, not automatic approval.
EvidenceSafety Measurement System Methodology: BASIC Prioritization Status, Version 3.21 2024 Pocket Guide to Large Truck and Bus Statistics
Translate the profile into a load decision
The useful question is not whether the carrier has a bad score. The useful question is whether the observed pattern touches the assigned driver, equipment, route, commodity, and schedule.
Vehicle maintenance issues matter more when the tender includes an unexplained trailer substitution. Hours issues matter more when the appointment math is already tight. Driver fitness issues matter more when the assigned driver cannot be independently verified. The profile should direct the next verification step.
| Observed pattern | Next verification | Possible control |
|---|---|---|
| Recent vehicle maintenance cluster | Assigned tractor and trailer inspection and repair file | Reject substitution or require documented equipment change |
| Recent hours pattern | Driver clock and route feasibility | Reset schedule or change driver before dispatch |
| Driver fitness pattern | License, medical, and assigned driver identity | No dispatch until the assigned driver is resolved |
| Hazardous materials pattern | Endorsement, permit, commodity, and route controls | Use a qualified hazmat review |
| Thin history | Age, identity, direct insurance, first-load controls | Cap exposure and monitor tightly |
EvidenceSafety Measurement System Methodology: BASIC Prioritization Status, Version 3.21
Recommended actions
- Display event dates and denominators beside every percentile.
- Route each BASIC pattern to a load-specific verification step.
- Recheck after new inspections, authority changes, equipment changes, and material claims.
Questions worth asking next
- Does your carrier score distinguish no data from clean data?
- Can a dispatcher see which recent events are driving the current signal?