What is a CSA score?

It gets called your “CSA score”, but FMCSA does not give you one number. It ranks you separately in seven safety categories, each as a percentile against carriers with a similar amount of inspection history. This guide explains what those percentiles are, how a roadside violation turns into one, who can see them and what changes them, using FMCSA’s own methodology.

What CSA and the SMS are

FMCSA describes CSA (Compliance, Safety, Accountability) as its “data-driven safety compliance and enforcement program.” It has three parts: the Safety Measurement System (SMS), interventions, and the Safety Fitness Determination rating system. The SMS is the part people mean by “CSA score”. It uses roadside inspections and crash reports from the last two years, plus results from investigations, to identify carriers with safety performance and compliance problems for interventions. FMCSA calls it its “workload prioritization tool.”

The seven BASICs

The SMS sorts your data into seven Behavior Analysis and Safety Improvement Categories (BASICs). Each roadside violation counts in the BASIC its regulation belongs to. The examples below are FMCSA’s own.

• Unsafe Driving: speeding, reckless driving, improper lane change, texting while driving, not wearing a seat belt.
• Crash Indicator: your history of State-reported crashes, by frequency and severity. Not publicly available.
• Hours-of-Service Compliance: driving while ill or fatigued, driving more than 11 hours, records of duty status.
• Vehicle Maintenance: brakes, lights and other mechanical defects, load securement, failing to make required repairs.
• Controlled Substances/Alcohol: use or possession, or failing to run a testing program.
• Hazardous Materials Compliance: marking, labeling, placarding and securing hazmat. Not publicly available.
• Driver Fitness: no valid CDL, a medically unqualified driver, missing driver qualification files.

How a violation becomes a percentile

1. Severity weight. Every violation gets a weight from 1 to 10 for how strongly it is associated with crash risk compared with the other violations in the same BASIC. An out-of-service violation adds 2 in the Hours of Service, Vehicle Maintenance, Hazmat and Driver Fitness BASICs. The same violation cited more than once on one inspection is used once, and one inspection can add at most 30 to a BASIC before the time weight.
2. Time weight. The weight is multiplied by 3 if the inspection was in the last six months, 2 if it was six to 12 months ago, and 1 if it was 12 to 24 months ago. After 24 months it no longer counts.
3. The measure. In the inspection-based BASICs, the SMS adds up those weighted violations and divides by the total time weight of your relevant inspections, including the ones with no violations. Unsafe Driving (whose violations, like speeding, are often what starts an inspection) and the Crash Indicator are divided by a measure of carrier size (power units and miles) instead.
4. The percentile. Carriers are grouped with others that have a similar number of inspections (or crashes), and each measure is ranked from 0 to 100. A higher percentile is worse.

A worked example

Take a hypothetical carrier with 10 vehicle inspections in the last 24 months: four in the last six months, three from six to 12 months ago and three from 12 to 24 months ago. The bottom of its Vehicle Maintenance fraction is 4 × 3 + 3 × 2 + 3 × 1 = 21.

Two months ago it got one tire violation, 393.75C-OOS (tread under 1/32 inch in two adjacent major grooves), and the truck was placed out of service. FMCSA’s methodology lists it at a severity weight of 8, plus 2 for out of service. Its weighted value is (8 + 2) × 3 = 30, so it adds 30 ÷ 21 ≈ 1.43 to the measure.

• One clean vehicle inspection this month adds 3 to the bottom: 30 ÷ 24 = 1.25.
• Thirteen months after that inspection, the same violation counts 10 instead of 30.
• If the violation came off the record through DataQs, the 30 comes off the top.

Where that leaves the percentile depends on the measures of the other carriers in the same group, which no example can show.

Why you may have no percentile in a BASIC

The SMS only ranks a carrier when it has enough data. In Hours of Service it needs at least three driver inspections that resulted in an Hours of Service violation; in Vehicle Maintenance, at least five vehicle inspections that resulted in a Vehicle Maintenance violation. A carrier with no violation in a BASIC in the past 12 months, and none on its latest relevant inspection, is also left unranked in that BASIC. No percentile does not mean no violations: they are still on your record.

Alerts and what they lead to

FMCSA sets an intervention threshold for each BASIC. At or above it, the carrier gets an alert symbol in that BASIC and may be prioritized for interventions such as warning letters and investigations, or for further monitoring. For most carriers the threshold is the 65th percentile in Unsafe Driving, Crash Indicator and Hours of Service, and the 80th in Vehicle Maintenance, Controlled Substances/Alcohol, Driver Fitness and Hazmat. Passenger carriers and hazmat carriers have lower thresholds in every BASIC except Hazmat, where all three are 80. A carrier can also get the alert from an acute or critical violation found in an investigation in the past 12 months.

Who can see your percentiles

Under the FAST Act of 2015, FMCSA says the SMS results for property carriers are “no longer available for public display. Property carriers must log in to view their complete SMS results.” The Crash Indicator and Hazmat BASICs are not public for any carrier. Complete results are available to enforcement users and to carriers logged into their own safety profile.

How often it updates

FMCSA updates the SMS once a month. According to the CSA FAQ, a snapshot of the data is taken on the third or last Friday of the month, and processing and validation take about 10 days before the website changes.

What moves it

• Time.Each violation’s weight drops at six and 12 months and disappears at 24.
• Clean inspections. In the inspection-based BASICs they add to the bottom of the fraction.
• Correcting wrong data.FMCSA’s advice to carriers is to review their inspection and crash reports and request corrections through DataQs if anything is wrong. The SMS leaves out violations that resulted from a crash, violations assigned only to another party such as a shipper, and violations whose citation was dismissed or found not guilty. It does use violations whether or not a ticket was issued. In a review, a detail the report simply leaves out is usually not enough, because the reviewer can check with the officer; a document that contradicts a fact on the report is what counts. See how to dispute a DOT violation and file a DataQ, an inspection on your record that isn’t yours and when your ticket was dismissed in court.

Two things that do not move it: a driver leaving your company (FMCSA says that driver’s inspections and crashes with you still apply to your SMS for 24 months), and an accurate violation, which no filing removes. It ages off at 24 months.

Sources

• FMCSA, SMS Methodology, Version 3.21 (methodology revised May 2026): the seven BASICs and their example violations (pp. 2-1 to 2-2), excluded violations (p. 2-3), severity weights, time weights, normalization, segmentation and percentile rank (pp. 2-4 to 2-7), intervention thresholds (Table 2-2), the measure, the cap of 30 and data sufficiency for Hours of Service and Vehicle Maintenance (pp. 3-11 to 3-16), the 393.75C-OOS tire weight (Table B-10), and public display under the FAST Act (p. 1-2, note 6).
• FMCSA, About CSA and FMCSA, We Measure: what CSA and the SMS are, monthly updates, who sees complete results.
• FMCSA, CSA FAQs: the monthly snapshot, a departed driver’s history, and requesting corrections through DataQs.