FMCSA · Safety Measurement System

How FMCSA measures a carrier, and what moves the numbers.

The Safety Measurement System (SMS) is the tool the Federal Motor Carrier Safety Administration uses to prioritize which carriers it monitors. This guide explains how a carrier's data becomes a score, what FMCSA does with it, and the levers that actually change it — in plain terms, with no judgment about any individual carrier.

0 — best measured performance100 — worst

Every public BASIC is scored as a percentile from 0 to 100 against carriers with a similar number of safety events. At or above the intervention threshold, a carrier is flagged with an Alert and may be prioritized for monitoring.

Read this first

An Alert is not a safety rating and not a finding of wrongdoing. Per the FAST Act of 2015, no one should conclude a carrier is unsafe from this data alone. Unless a carrier holds a final Unsatisfactory rating or has been ordered to stop operating, it is authorized to operate. SMS measures relative performance and prioritizes FMCSA's attention — nothing more.

7 BASICs · 5 shown publicly24-month rolling data windowUpdated monthly from MCMIS

How a carrier is measured

SMS sorts a carrier's roadside inspections, crashes, and investigation findings into seven Behavior Analysis and Safety Improvement Categories (BASICs), then turns each into a relative score. It covers interstate carriers operating vehicles rated 10,001 lbs or more, plus intrastate carriers hauling placardable hazardous materials.

The seven BASICs

FMCSA lists the BASICs in order of how strongly each correlates with crash risk — established by its SMS Effectiveness Test — so the categories most tied to crashes come first. Five of the seven BASICs are shown publicly. Crash Indicator and HM Compliance are calculated but hidden from public view; the Insurance/Other Indicator (not one of the seven BASICs) comes only from investigations and is also not public. CrimReport never displays the non-public categories as if they were available.

Unsafe Driving

Public

Operating a vehicle dangerously or carelessly — speeding, reckless driving, improper lane changes, texting, no seatbelt.

Regs Parts 392, 397From driver inspections · L1/2/3/6

Crash Indicator

Not public

Historical pattern of crash involvement by frequency and severity, from State-reported reportable crashes.

From state crash reportsCounts regardless of fault

HOS Compliance

Public

Hours-of-service and records-of-duty-status problems — driving over the limit, false or missing logs, ill or fatigued operation.

Regs Parts 392, 395From driver inspections · L1/2/3/6

Vehicle Maintenance

Public

Mechanical and securement failures — brakes, lights, defects, improper load securement, deferred repairs.

Regs Parts 392, 393, 396From vehicle inspections · L1/2/5/6

Controlled Substances / Alcohol

Public

Impaired operation from alcohol, illegal drugs, or misuse of medication; use or possession on duty.

Regs Parts 382, 392From driver inspections · L1/2/3/6

HM Compliance

Not public

Unsafe handling of hazardous materials — placarding, packaging, leaking containers, missing cargo-tank tests.

Regs Part 397 + HMR 171–180From placardable HM inspections

Driver Fitness

Public

Drivers unfit by training, experience, or medical qualification — invalid CDL, medically unqualified, missing qualification files.

Regs Parts 383, 391From driver inspections · L1/2/3/6

Insurance / Other Indicator

Not public

Registration, insurance, and reporting failures — found only during investigations, not roadside.

From investigations onlyNo percentile shown

Inspection levels

Inspections come in levels I–VI. Driver inspections (Levels 1, 2, 3, 6) feed Unsafe Driving, HOS, Controlled Substances/Alcohol, and Driver Fitness. Vehicle inspections (Levels 1, 2, 5, 6) feed Vehicle Maintenance. Placardable HM inspections are vehicle inspections carrying placardable quantities of hazardous materials, and feed HM Compliance.

From data to a score

Each violation is weighted, summed, normalized for the carrier's exposure, and ranked against peers. Here's what each step does.

Time weight

Recent events count more. A violation in the last 6 months ×3, 6–12 months ×2, 12–24 months ×1. After 24 months it drops off entirely.

Severity weight

Each violation carries 1–10 by crash risk, plus +2 if it caused an out-of-service order (in the applicable BASICs). Weights are not comparable across BASICs — a 5 in one isn't a 5 in another. Per-inspection severity is capped at 30 before time-weighting. The full per-violation weight tables aren't reproduced here.

Measure

The weighted total, divided by the carrier's exposure. A measure of 0 is best; it reflects the carrier alone, not a comparison.

Normalization

Unsafe Driving and Crash Indicator divide by carrier size (see Exposure below). The other BASICs divide by the number of relevant inspections — including the ones that found nothing.

Exposure (size)

For the size-normalized BASICs, SMS uses an average power-unit count — today's PUs, plus the count 6 months ago, plus the count 18 months ago, divided by 3 — paired with annual vehicle miles traveled. Averaging smooths out fleet changes, which is why a current MCS-150 matters.

Segmentation

For Unsafe Driving and Crash Indicator only: Combination (combo trucks / coaches ≥70% of fleet) vs Straight (straight trucks / other >30%), so unlike operations aren't compared.

Safety event group

Carriers are ranked only against others with a similar number of safety events, so a 10-truck fleet isn't measured against a 10,000-truck fleet.

Percentile

Within the group, the measure becomes a 0–100 percentile. The highest measure in the group sits at 100, the lowest at 0. Higher is worse. This is the number you see.

How crashes count

A reportable crash (49 CFR 390.5) is one involving a qualifying commercial vehicle on a public road that results in a fatality, an injury, or a tow-away for disabling damage. Reportable crashes are counted regardless of who was at fault — State crash reports don't record fault, and FMCSA's research shows prior crash involvement predicts future risk either way — except where FMCSA has reviewed a crash and determined it Not Preventable (see below). Crashes are severity-weighted: those involving injuries, fatalities, or a hazardous-materials release weigh more than tow-away-only crashes.

Crash Preventability Determination Program (CPDP)

A carrier can ask FMCSA to review an eligible crash. If it's determined Not Preventable, the crash is marked reviewed and excluded from the Crash Indicator measure. This is a permanent program — not the time-limited demonstration it began as.

Minimum data to be scored

A carrier isn't ranked until there's enough data to be meaningful. Below those minimums, the BASIC shows a status instead of a percentile.

BASIC	Minimum to receive a percentile
Unsafe Driving	3+ inspections with a violation
Crash Indicator	2+ crashes
HOS Compliance	3+ relevant driver inspections, 1+ with a violation
Vehicle Maintenance	5+ relevant vehicle inspections, 1+ with a violation
Driver Fitness	5+ relevant driver inspections, 1+ with a violation
HM Compliance	5+ placardable HM inspections, 1+ with a violation
Controlled Substances / Alcohol	1+ inspection with a violation

Safety event group breakpoints

Within each BASIC, carriers are slotted into one of five groups by how many safety events they have, then ranked only against that group. The boundaries:

Reading the status labels

When there's no percentile, SMS shows one of these. They mean "not enough data," not "good" or "bad."

0% — enough inspections, no violations in this BASIC

< 3 / < 5 inspections with violations — too few to rank

No violations within 1 year — none in the last 12 months

No PU data — no registered power units on file

< 5 vehicle inspections — not enough to assess

No HM placardable inspections — no relevant HM activity

Out-of-service rates

Separate from the BASIC percentiles, SMS reports out-of-service (OOS) rates with national averages for comparison. The driver OOS rate is driver inspections with at least one driver OOS violation divided by all driver inspections; the vehicle and HM rates work the same way for their inspection types.

Where the data comes from

SMS pulls a monthly snapshot from FMCSA's national database (MCMIS): the previous 24 months of roadside inspections and State-reported crashes, plus Federal and State investigation results from the previous 12 months. It updates once a month, so a correction or a clean stretch shows up on the next cycle, not instantly.

What FMCSA does with it

Scores and investigation findings feed a graduated set of actions. Crossing a threshold or being found with a serious investigation violation puts a carrier on FMCSA's radar.

Intervention thresholds

At or above the threshold for a BASIC, the carrier earns an Alert. The highest-crash-risk categories have the lowest (strictest) thresholds. Passenger and HM carriers are held to tighter limits because the consequences are greater.

BASIC group	Passenger	HM	General
Unsafe Driving · Crash Indicator · HOS Compliance	≥50%	≥60%	≥65%
Vehicle Maintenance · Controlled Substances/Alcohol · Driver Fitness	≥65%	≥75%	≥80%
HM Compliance	≥80%	≥80%	≥80%

Which column applies

A carrier falls under the HM thresholds if it has at least two placardable-HM inspections in the last 24 months (one of them in the last 12) and placardable-HM inspections are at least 5% of its vehicle inspections — or, by a separate path, it holds an HM safety permit. It falls under the Passenger thresholds under FMCSA's passenger-carrier criteria — broadly, operating passenger-capacity vehicles where those vehicles exceed 2% of power units (the exact test varies by operating authority and capacity). Everyone else is General.

An Alert can also appear with no threshold crossed — if an Acute or Critical violation was found in that BASIC during an investigation in the last 12 months.

Interactive · Published thresholds only

Threshold checker

Pick a carrier type and a BASIC to see exactly where the Alert line sits. This uses FMCSA's published thresholds — no carrier data is involved. Crash Indicator and HM Compliance have published thresholds too, shown here for completeness, even though their percentiles aren't publicly displayed.

Carrier type

BASIC

050100

A General carrier is flagged with an Alert in Unsafe Driving at or above the 65th percentile — or with any Acute/Critical violation in this BASIC.

How FMCSA intervenes

Interventions escalate only as needed, across three broad stages — though FMCSA tailors the path to the carrier rather than marching through a fixed sequence. Most carriers never go past the first stage.

1 · Early contact

Warning letter

Early notice, based on 24 months of roadside performance, that one or more BASICs are at or near threshold. No written response required — a prompt to review your data, sent to the principal place of business.

Targeted roadside inspection

Inspectors are given a carrier's weak BASICs so roadside checks focus where the data points.

2 · Investigation

Offsite investigation

Remote review of documents the carrier provides, aimed at a specific emerging problem.

Onsite focused investigation

An investigator visits the principal place of business to examine a specific problem area.

Onsite comprehensive investigation

A full review of the carrier's operation at its place of business.

3 · Follow-on actions

Cooperative Safety Plan (CSP)

A voluntary plan a carrier can adopt to correct identified problems.

Notice of Violation (NOV)

Formal notice of violations requiring a corrective response.

Notice of Claim

Commences a civil-penalty proceeding where violations warrant it.

Operation Out-of-Service Order

The most serious step — an order to cease operations.

A safety rating is not an intervention — it's a possible outcome of an onsite compliance review (see below).

Acute & Critical violations

These come from investigations, not roadside. An Acute violation is a single occurrence severe enough to require immediate correction. A Critical violation is a pattern — found in at least 10% of records checked, with more than one occurrence. Either one, in the last 12 months, triggers an Alert on its own, regardless of percentile.

Safety ratings are a separate thing

BASIC percentiles and safety ratings are not the same. A rating comes only from an onsite compliance review against the safety-fitness standard (49 CFR 385.5), and there are three:

Rating	Meaning
Satisfactory	Controls are adequate to meet the safety-fitness standard (issued only from a full-scope review).
Conditional	Controls are inadequate but haven't yet caused a standard violation.
Unsatisfactory	Controls are inadequate and have caused violations. A final Unsatisfactory rating prohibits interstate operation.

A carrier with no rating is still authorized to operate. "Unrated" is common and is not a negative finding.

How a carrier improves

Scores move two ways: fix the underlying safety management, and make sure the data on record is accurate. Both matter.

FMCSA's five steps

Understand the FMCSRs and (if you carry hazmat) the HMRs, and act on the trends in your own violation history. Each BASIC maps to specific parts of the regulations.

The Safety Management Cycle

FMCSA's diagnostic framework. It looks at why violations happen by walking six processes in order — a breakdown in any one shows up as violations downstream.

SMP 1

Policies & Procedures

The written "what" and "how" of your operation.

SMP 2

Roles & Responsibilities

Who is accountable for carrying each one out.

SMP 3

Qualification & Hiring

Finding and screening the right people for those roles.

SMP 4

Training & Communication

Making sure everyone has the skills and knows the expectations.

SMP 5

Monitoring & Tracking

Watching performance and reviewing the data it produces.

SMP 6

Meaningful Action

Correcting or reinforcing behavior based on what you tracked.

Applying it — four steps

Review your SMS history for trends → assess each process to find where it's breaking down → work out why, and pick Safety Improvement Practices (SIPs) to fix it → prioritize, implement for your size and resources, and track the effect on your percentiles over time.

Worked example · FMCSA case study

A small carrier diagnoses a HOS problem

BASIC: HOS ComplianceSymptom: false / not-current logsTrigger: over threshold → warning letter → onsite

A small auto-transport carrier kept crossing the HOS threshold, driven by repeated "false logs" and "logs not current" violations. A warning letter went unaddressed, and six months later an investigator scheduled an onsite review.

Walking the six processes together, the policies, roles, hiring, and the logs themselves were all in place — the breakdowns were in Training & Communication and Monitoring & Tracking. Drivers didn't know the HOS rules or the reason behind them, and the person assigned to review logs had never been trained to cross-check them against fuel, toll, and trip receipts, so falsifications slipped through and drivers got no feedback.

The fix followed directly: train drivers on the HOS rules and why accurate logs matter, and train the reviewer to verify logs against supporting documents. Over the following months the roadside results improved and the carrier dropped back below the threshold — and avoided escalation to penalties. (Illustrative example; not a real carrier.)

By BASIC — where to look

Analyze your own data

FMCSA recommends downloading your violation data and reading it the way an investigator would:

Group similar violations

Bucket related codes (all speeding, all tire issues) and see which groups recur most — that's where the process gap is.

Weight by frequency × severity

Multiply how often a violation appears by its severity weight to rank what's actually moving your score.

Sort by driver, date & State

Look for a single driver, a season, or a corridor behind a cluster — it points to the root cause.

Separate by vehicle type

In Vehicle Maintenance and HM, check whether certain trucks or trailers drive the violations.

The mechanical levers

Recency works for you

Recent events weigh most and everything drops off at 24 months. A sustained clean stretch moves the score faster than anything else.

Clean inspections help directly

In the inspection-normalized BASICs, each clean relevant inspection grows the denominator and lowers the measure.

Fix out-of-service conditions

OOS violations carry an extra +2 severity in several BASICs — resolving them removes outsized weight.

Keep size data accurate

SMS averages your power units over 18 months and uses annual VMT — a current MCS-150 keeps the Unsafe Driving and Crash Indicator math honest.

Challenge bad data (DataQs)

A dismissed/not-guilty citation removes the violation; "convicted of a different charge" drops it to severity 1.

Crash Preventability (CPDP)

A crash FMCSA determines "Not Preventable" is shown as reviewed and excluded from the Crash Indicator measure.

Correcting your data — DataQs

DataQs is FMCSA's request-for-data-review system. Register, then file with the report number, the date, time, and State of the event, an explanation, and any supporting documents. The request routes to the agency responsible for the record. Adjudicated-citation outcomes apply only to inspections on or after August 23, 2014, and citations (State court) and roadside violations (DataQs) must be challenged separately — one doesn't resolve the other.

Reference

Key terms and notes on this guide.

Glossary

BASIC: One of seven Behavior Analysis and Safety Improvement Categories SMS sorts data into.
Measure: A carrier's time- and severity-weighted total in a BASIC, normalized for exposure. 0 is best.
Percentile: The measure ranked 0–100 against a safety event group. Higher is worse.
Safety event group: Carriers with a similar number of inspections, violations, or crashes — the peer set you're ranked against.
Intervention threshold: The percentile at or above which a carrier is flagged with an Alert.
Alert: The symbol shown when a BASIC is at/over threshold or has an Acute/Critical violation. Not a safety rating. FMCSA's current methodology calls this the BASIC Prioritization Status.
Reportable crash: A qualifying CMV crash on a public road resulting in a fatality, injury, or tow-away (49 CFR 390.5). All count, regardless of fault — except crashes determined Not Preventable.
Power unit (PU): A vehicle a carrier owns, trip-leases, or term-leases. Averaged over 18 months and paired with VMT to size exposure.
VMT: Vehicle miles traveled over the last two years, from the MCS-150. Feeds the Unsafe Driving and Crash Indicator measures.
Relevant inspection: An inspection of the type that looks at a given BASIC — including ones that found no violation.
Inspection levels: I–VI. Driver = 1/2/3/6; Vehicle = 1/2/5/6; Placardable HM = vehicle inspections carrying placardable HM.
Out-of-service (OOS): A condition serious enough to bar the driver or vehicle from operating until fixed. Adds +2 severity in the BASICs where it applies.
OOS rate: Inspections of a type with at least one OOS violation, divided by all inspections of that type. Shown with national averages.
Acute / Critical violation: Investigation findings — a single severe occurrence, or a pattern across records — requiring corrective action.
Compliance review: An onsite examination of a carrier's operations against the safety-fitness standard (49 CFR 385.5).
Notice of Claim: The formal notice FMCSA issues to begin a civil-penalty proceeding (49 CFR 386.11).
MCS-150: The Motor Carrier Identification Report; carrier registration data, updated at least every two years.
MCMIS: FMCSA's national database; SMS takes a monthly snapshot from it.
DataQs: The system for requesting review or correction of FMCSA data.
CPDP: Crash Preventability Determination Program — reviews whether an eligible crash was preventable.
SIP: Safety Improvement Practice — a specific fix identified through the Safety Management Cycle.
Safety rating: Satisfactory, Conditional, or Unsatisfactory — issued only from an onsite compliance review.
Effectiveness Test: FMCSA's analysis confirming that higher BASIC percentiles correlate with higher future crash rates.

Related guides

About this guide

Current as of June 2026. This guide reflects the SMS methodology in effect today. FMCSA has proposed a future overhaul — the CSA Prioritization Preview — that would change parts of how carriers are scored; nothing here assumes those changes are live yet.

This guide is educational. It summarizes how the Safety Measurement System works and does not modify or replace FMCSA regulations or any substantive standard, and it is not legal advice. Always consult the current Federal Motor Carrier Safety Regulations. SMS data describes relative performance for prioritization; it is not a determination that any carrier is safe or unsafe.