What is a CSA score, and how do the BASICs work?
CSA — Compliance, Safety, Accountability — is FMCSA's safety compliance and enforcement program, and what carriers call a "CSA score" is produced by its Safety Measurement System. SMS takes 24 months of roadside-inspection violations and state-reported crashes, weights each violation from 1 to 10 by severity and by how recently it was recorded, divides by your fleet size and how hard you run it, then ranks you only against carriers with a similar number of safety events and converts that rank into a percentile from 0 to 100 in each of seven BASICs. Higher is worse. At or above the intervention threshold for a BASIC you are prioritized for intervention and marked with an alert — 65 percent for Unsafe Driving, Crash Indicator and HOS Compliance, 80 percent for Vehicle Maintenance, Controlled Substances/Alcohol and Driver Fitness, at a general freight carrier. A CSA percentile is not a safety rating, and since the FAST Act a property carrier's complete results are visible only to that carrier, after logging in.
Intervention thresholds, by BASIC and carrier type
A percentile means nothing on its own — only against the threshold for that BASIC and your kind of operation. Passenger and hazardous-materials carriers are held to a lower number in almost every category, so the same percentile that is unremarkable for a dry-van fleet is an alert for a motorcoach.
| BASIC | Passenger carrier | HM carrier | General |
|---|---|---|---|
| Unsafe Driving | 50% | 60% | 65% |
| Crash Indicator | 50% | 60% | 65% |
| HOS Compliance | 50% | 60% | 65% |
| Vehicle Maintenance | 65% | 75% | 80% |
| Controlled Substances/Alcohol | 65% | 75% | 80% |
| Driver Fitness | 65% | 75% | 80% |
| HM Compliance | 80% | 80% | 80% |
How your number is actually built
The data: roadside inspections, state-reported crashes, and investigations
Two streams feed the measurement and neither is optional for you. Roadside inspections come first: any violation written on a driver or vehicle inspection that appears in the SMS violation list counts, whether or not the driver was ticketed and whether or not anything was placed out of service. Second are crashes reported by the states that meet the reportable standard, which feed the Crash Indicator. A third path bypasses measurement altogether — an acute or critical violation found during an investigation in the last 12 months puts an alert on the matching BASIC by itself, with no percentile involved.
Severity weight first, then time weight
Every countable violation carries a severity weight from 1 to 10, published violation by violation in the SMS Appendix A. The weights from one inspection in one BASIC are capped at 30 in total, so a single catastrophic inspection cannot dominate the measure the way a pattern of them does. Then age multiplies it: a violation recorded in the past six months is weighted 3, one between six and twelve months is weighted 2, and one from twelve up to twenty-four months is weighted 1. Past twenty-four months it leaves the calculation entirely — which is why a bad year genuinely does age off, on a schedule you can count on a calendar.
Divide by exposure — and the divisor is not the same in every BASIC
What the weighted total is divided by depends on the BASIC. Unsafe Driving and the Crash Indicator are divided by carrier size: your average power units — the current count, the count six months ago and the count eighteen months ago, averaged — adjusted by a utilization factor derived from the miles you reported per power unit. The other BASICs are divided by your relevant inspections instead, which is why a clean inspection helps there and does nothing for the first two. Either way, three violations mean something very different for a forty-truck fleet and for an owner-operator. And where the utilization factor applies, the MCS-150 you update every 24 months is not a formality: the mileage on it is a direct input, and a carrier that under-reports its miles makes its own number worse.
You are compared only with carriers that look like you
SMS does not rank you against the industry. It sorts carriers into a combination segment and a straight segment, then into safety event groups by how many inspections with violations they have — five groups per segment — and ranks within the group before converting to a percentile from 0 to 100. Below a data-sufficiency floor there is no percentile at all: in Unsafe Driving, fewer than three inspections with a violation and you are not ranked. A new carrier with two bad inspections has no score, which is not the same thing as a good one.
Cross the threshold, and FMCSA acts
At or above the intervention threshold in a BASIC you are prioritized and marked with an alert symbol. What follows escalates rather than arriving all at once: a warning letter, then targeted roadside inspections, then an offsite investigation, an onsite focused investigation, or an onsite comprehensive investigation — the last of which can end in a safety rating. The thresholds are in the table above, and the acute-and-critical route ignores them completely.
Fix the record that is wrong and the behavior that is not
These are two different jobs. Data that is factually wrong is challenged through DataQs, FMCSA's request-for-data-review system. A crash your driver could not have prevented goes to the Crash Preventability Determination Program: if FMCSA agrees, the crash is displayed as "Reviewed – Not Preventable" and is excluded from your Crash Indicator measure and percentile. Data that is right only improves on the calendar — fix the underlying behavior, accumulate clean inspections, and let the time weights do the rest.
Common questions
Is a CSA score the same as a safety rating?
No, and confusing the two costs carriers real money. A safety rating — Satisfactory, Conditional, Unsatisfactory — comes out of a compliance review and is a formal determination about your fitness to operate. A CSA percentile is a workload prioritization tool, and FMCSA describes it in exactly those words: it helps the agency decide whom to look at next. You can be prioritized in two BASICs and hold no rating at all, and you can carry a Satisfactory rating from years ago while every BASIC sits over threshold.
How long does a violation count against me?
Twenty-four months in the calculation, weakening as it goes: weight 3 for the first six months, 2 for the next six, 1 for the final year, then nothing. The inspection itself remains visible in FMCSA's data for longer than that; what ages off is its effect on the percentile. A correctly recorded violation cannot be removed — the two real exceptions are a DataQs correction of something factually wrong, and the adjudicated citation result, where a dismissal or a conviction on a different charge changes how the violation is counted.
Can brokers and insurers see my score?
Not all of it. Since the FAST Act of 2015, a property carrier's complete SMS results are no longer publicly displayed — the carrier logs in to see them in full — and the Crash Indicator and HM Compliance BASICs are not publicly available to anyone. What remains public is your inspection and crash history and your investigation results, which is already more than enough for a broker or an underwriter to form a view. Assume they look, because they do.
The crash was not our driver's fault. Does it still count?
By default, yes — the Crash Indicator counts state-reported crashes without asking who caused them. The exception is the Crash Preventability Determination Program: an eligible crash submitted through DataQs and determined by FMCSA to be not preventable is displayed as "Reviewed – Not Preventable" and excluded from your measure and your percentile. It is neither automatic nor retroactive to crashes you never submitted, so it only helps the carriers who file.
My percentile went up and I had no new violations. How?
Because it is a rank, not a score. Your measure can be unchanged while the other carriers in your safety event group improve, and your percentile rises anyway. The same effect runs in reverse through the denominator: fleet size and reported mileage are both in it, so a carrier that shrinks its fleet without shrinking its violation history gets worse on paper. This is also the honest answer to "what is a good CSA score" — there is no absolute number, only your percentile against the threshold for your BASIC and your carrier type.
FMCSA is rewriting all of this. Do I need to care yet?
Not yet — and specifically not yet. FMCSA has a revised methodology that reorganizes roughly two thousand violation codes into about a hundred groups, splits Vehicle Maintenance into what an inspector can see on a walk-around and what only turns up in the shop, folds Controlled Substances/Alcohol into Unsafe Driving, and renames the BASICs "compliance categories". It is published as the CSA Prioritization Preview so carriers can see their own results under it before it takes effect. FMCSA's own instruction is unambiguous: until the updated system is in effect, use the current SMS website to monitor your safety performance. Watch it; do not plan around it.
Sources
- FMCSA SMS Methodology, Version 3.21 (June 2026) — the document every number on this page comes from — severity and time weights, safety event groups, data sufficiency, and the threshold table above
- FMCSA Safety Measurement System — your own results; a property carrier has to log in to see them in full
- 49 CFR Part 385, Appendix B — the acute and critical violations that put an alert on a BASIC with no percentile involved
- FMCSA DataQs — where a factually wrong inspection or crash record is challenged, and where a crash is submitted for a preventability determination
- CSA Prioritization Preview — the revised methodology, in preview only — FMCSA's instruction is to keep using the current SMS until it is in effect
Updated
This guide is general information about US federal and state transportation regulation — it is not legal or tax advice, and reading it does not make you our client. Rules change, and how one applies depends on your own operation: check anything you intend to rely on against the primary source above, or call us and we will check it with you.