Most carriers know their CSA score exists. Far fewer understand what actually drives it — or what it costs them when it's bad.

A high CSA score in the wrong category can add 20–40% to your annual insurance premium, get you blacklisted by major freight brokers, and trigger a federal compliance review that can end your operating authority. A clean CSA score does the opposite: it puts you in the preferred carrier tier with brokers, earns better insurance pricing, and keeps FMCSA's attention directed elsewhere.

The system is more nuanced than "violations are bad" — the timing of violations matters, the category they fall into matters, and the number of inspections you've had changes how your percentile is calculated. Most carriers know their score is a number between 0 and 100 and that lower is better. This guide covers what actually determines that number and what you can do about it.

What CSA Is and Why It Exists

CSA stands for Compliance, Safety, Accountability. It's FMCSA's data-driven safety monitoring system — a way for the agency to identify carriers with elevated crash risk without physically inspecting every truck on the road every day.

The core idea: rather than reacting to crashes after they happen, FMCSA uses roadside inspection data, violation history, and crash records to identify carriers whose operational patterns suggest future risk. Carriers who score poorly get attention first — warning letters, targeted inspections, compliance reviews. Carriers with clean records operate without that scrutiny.

CSA doesn't give you a single score. It gives you a percentile ranking in seven separate categories, called BASICs (Behavior Analysis and Safety Improvement Categories). Your percentile in each BASIC tells you how you compare to all other carriers with similar inspection history. A 75th percentile means 75% of comparable carriers have better scores than you in that category — which is bad. A 20th percentile means 80% of comparable carriers have worse scores — which is good.

The Seven BASICs: What Each One Measures

Understanding which category a violation falls into is critical, because the intervention thresholds and insurance impact differ significantly across categories.

1. Unsafe Driving

The most watched BASIC. Captures speeding, reckless driving, improper lane changes, following too closely, and distracted driving (including phone use). Unsafe Driving has the strongest statistical correlation with crash risk of any BASIC — FMCSA research consistently shows it's the best predictor of future crash involvement.

Intervention threshold: 65th percentile for most carriers; 50th percentile for new entrant carriers (under 18 months of authority).

Insurance impact: High. Underwriters treat elevated Unsafe Driving scores as a direct signal of future claim risk. A carrier at the 85th percentile for Unsafe Driving should expect 20–40% higher premiums than a comparable carrier with a clean score in this category.

What generates violations here: Any speeding citation at roadside, following distance violations, lane change violations, and cell phone use. These come from both roadside inspections and law enforcement citations that get reported to FMCSA.

2. Hours of Service Compliance

Tracks violations of HOS rules — driving beyond the 11-hour limit, operating outside the 14-hour window, falsified logs, and missing or non-compliant ELD records. The data comes from roadside inspections where an officer reviews your ELD records.

Intervention threshold: 65th percentile.

What changed in 2026: The SMS overhaul doubled the severity weight of out-of-service HOS violations to a weight of 2 (non-OOS violations stay at weight 1). A single OOS HOS violation — driving beyond the 11-hour limit, for instance — now hits your percentile twice as hard as it did before the overhaul.

What generates violations here: Running past your 11-hour limit, driving after the 14-hour window closes, missing the 30-minute break requirement, and log falsification. ELD errors that cause the device to incorrectly log off-duty time can also generate violations even without intentional misconduct — which is why choosing a reliable ELD and knowing how to use it correctly matters.

3. Driver Fitness

Covers driver qualification violations — operating with an expired CDL, missing or outdated medical certification, operating outside CDL endorsements, and unqualified driver issues. This is an administrative BASIC more than an operational one.

Intervention threshold: 80th percentile (higher threshold, meaning more tolerance before FMCSA intervenes).

What generates violations here: Expired CDL at roadside inspection, medical certification not current on CDL record (as of January 2026, medical certification is verified through state MVR records for CDL holders, not a paper card), operating a vehicle that requires an endorsement the driver doesn't have.

4. Controlled Substances and Alcohol

Any drug or alcohol violation — positive test result, refusal to test, operating under the influence. This BASIC has the lowest tolerance of any category, because the presence of controlled substances or alcohol in a commercial driver is treated as near-absolute by FMCSA.

Intervention threshold: 80th percentile — but a single serious violation here can push a carrier above threshold instantly.

What generates violations here: Failed roadside drug or alcohol test, refusal to submit to testing, operating with a detectable blood alcohol level, and violations discovered through the FMCSA Drug and Alcohol Clearinghouse.

5. Vehicle Maintenance

The highest-volume BASIC for most carriers. Covers all mechanical violations found at roadside inspections — brake defects, tire issues, lighting violations, cargo securement defects, and equipment that doesn't meet Federal Motor Carrier Safety Standards.

Intervention threshold: 80th percentile.

The most common OOS violations: Brake adjustment and brake system violations consistently account for 30%+ of out-of-service orders at roadside inspections. Tire tread depth and condition is second. Lighting violations are the most common non-OOS vehicle maintenance violations.

What changed in 2026: FMCSA's SMS overhaul created a new "Vehicle Maintenance: Driver Observed" category that separates equipment defects discovered by inspectors from defects a thorough pre-trip could have caught. Carriers with documented, systematic pre-trip inspection programs are rewarded in the new structure — because their defects get caught and corrected before an inspector sees them.

6. Hazardous Materials Compliance

Only applies to carriers who haul hazmat. Covers placarding violations, shipping paper errors, package securement, and emergency response information. If you don't haul hazmat, this BASIC is not scored for your operation.

Intervention threshold: 60th percentile — lower than most other categories, reflecting the severity of hazmat incidents.

7. Crash Indicator

Measures crash history relative to comparable carriers, weighted by crash severity. Unlike the other BASICs — which are driven by inspection violations — Crash Indicator is driven by actual crash involvement. It's calculated separately and uses a different methodology.

Intervention threshold: 65th percentile.

Important distinction: Crash Indicator captures crashes that are reported to FMCSA, but it doesn't distinguish at-fault from not-at-fault in most cases. Being rear-ended at a red light can affect your Crash Indicator score even if you had zero fault. This is one of the most criticized aspects of the CSA system — crashes you didn't cause still count against you until and unless you successfully dispute them.

How the Scoring Actually Works: Points, Severity, and Time Weighting

Your CSA percentile isn't calculated from a raw violation count. It's calculated from a weighted violation score that accounts for severity and recency.

Severity weighting: Violations are assigned weights from 1 to 10. A basic equipment defect like an inoperative turn signal might be weight 2. Running a stop sign is weight 4. Speeding 15+ over the limit is weight 7. Driving under the influence is weight 10. More dangerous violations move your score more than minor ones.

Time weighting: The 24-month window isn't flat. Violations carry different weight based on recency:

• Last 6 months: full weight (multiplier of 3)
• 7–12 months ago: moderate weight (multiplier of 2)
• 13–24 months ago: reduced weight (multiplier of 1)
• Beyond 24 months: removed entirely

A violation from 18 months ago has one-third the impact of the same violation from 3 months ago — and zero impact at 25 months. A carrier who had a bad stretch two years ago can fully rebuild their percentile through clean operation within the 24-month window.

Out-of-service multiplier (2026 change): OOS violations are now weighted at 2× the normal violation severity under the 2026 SMS overhaul. A weight-7 speeding violation that generated an OOS order now effectively scores as weight 14. This makes avoiding OOS orders considerably more important than avoiding non-OOS violations — a distinction that wasn't as sharp before the overhaul.

The inspection volume factor: Your percentile is a comparison against carriers with similar inspection histories. Carriers with fewer than 3 inspections in a BASIC category may not have a calculated percentile at all. As inspections accumulate, your percentile stabilizes. This is why carriers with few inspections see dramatic swings from a single violation or clean inspection — there's not enough data to dilute the impact.

Intervention Thresholds: What Happens When You Cross One

Exceeding a threshold doesn't automatically shut you down. FMCSA uses a graduated intervention ladder:

Warning letter: The first step for most threshold exceedances. FMCSA identifies which category is elevated and requests corrective action. No audit, no immediate operational impact.

Targeted roadside inspections: Carriers above threshold in priority BASICs get flagged in inspection systems. Weigh station inspectors are alerted to prioritize your trucks.

Offsite investigation: FMCSA requests records — HOS logs, driver qualification files, maintenance records — without conducting a full on-site audit.

On-site compliance review: A full safety audit. This is the serious intervention. Results can include a Conditional or Unsatisfactory safety rating, which affects insurance pricing, broker access, and your ability to haul certain freight.

Compliance order, revocation, or suspension: The end of the escalation chain. Carriers who don't correct deficiencies after a compliance review can face revocation of operating authority.

The intervention threshold for new entrant carriers is 50th percentile for Unsafe Driving — lower than the 65th percentile for established carriers. New carriers have less margin, not more.

What a Bad CSA Score Actually Costs

Insurance: Underwriters pull FMCSA SMS data during every policy application and renewal. The premium impact is direct and significant. An Unsafe Driving BASIC above the 50th percentile typically adds 20–35% to your annual premium. Above the 75th percentile, expect 30–50%+. Multiple BASICs above intervention threshold can cause standard carriers to decline to quote entirely, pushing you into high-risk specialty markets at substantially higher rates. On a $12,000 base policy, a 35% increase is $4,200/year — every year the score stays elevated.

Broker access: Major freight brokers and shippers check CSA scores before assigning loads. Many have internal policies that prohibit using carriers above certain percentiles in Unsafe Driving or Crash Indicator — thresholds stricter than FMCSA's intervention levels. A carrier cut off from the largest brokers is competing in a smaller, lower-rate market.

Load rates: More broker access means more leverage. Carriers with clean records can shop loads and hold out for better rates. Carriers with elevated scores take what they can get, which is usually lower-quality freight at lower rates.

How to Check Your Score

Your CSA data is publicly available at ai.fmcsa.dot.gov/SMS. Any carrier, broker, or shipper can look up your scores by USDOT number — which means they already are. Log in with your USDOT number and PIN to see your full violation history, severity points, and which violations are driving each BASIC.

The 2026 preview tool at csa.fmcsa.dot.gov/prioritizationpreview lets carriers see how their scores look under the updated methodology before it's fully implemented — worth checking if you're near a threshold in any category.

How to Actually Improve Your Score

The only way to improve your CSA score is to accumulate clean inspections while old violations age off. There are no programs to enroll in, no fees to pay, and no shortcuts.

Prevent violations before they happen. Vehicle Maintenance violations — the most common category — are almost entirely preventable with a consistent pre-trip. Brakes, tires, and lights account for the majority of OOS orders. A 15-minute pre-trip that catches a soft tire beats an OOS order that takes you off the road and stays on your record for two years.

Understand which violations carry the most weight. Speeding 15+ over the limit, HOS OOS violations, log falsification, and drug/alcohol violations carry the highest severity weights. One of these moves your percentile more than five minor equipment violations combined. Your prevention priority order should match the severity weighting.

Accumulate clean Level 1 inspections. A Level 1 inspection with zero violations adds a clean, high-weight data point to your record. Operators who avoid weigh stations to minimize inspection exposure are preventing the clean inspections that would improve their scores. Go through, run clean, build the record.

Dispute incorrect violations through DataQs. FMCSA's DataQs system allows challenges to violations recorded in error or not correctly applied. Inspection findings are generally upheld unless there's clear documentation — but genuinely erroneous violations are worth disputing. A successfully challenged violation is removed from your record.

Monitor your record every 30–60 days. Know which violations are aging off and when, and know which recent violations are weighing your percentile most heavily. Carriers who check their SMS data regularly can catch emerging problems before they cross intervention thresholds.

Bottom Line

Your CSA score is a real-time picture of your operation's safety profile — one that insurers, brokers, and FMCSA check continuously. It's built from roadside inspections across seven categories, weighted by severity and recency, and compared against peers to generate a percentile.

The most important things to understand: Unsafe Driving carries the highest insurance impact and lowest intervention threshold. Out-of-service violations now count double under the 2026 SMS overhaul. New carriers are more vulnerable to percentile swings than established ones. And the only path to a better score is clean inspections over time — there's no fast path.

The carriers who protect their CSA record do it the same way: pre-trips every day, legal HOS every trip, and a truck maintained well enough that an inspector finds nothing worth writing. It's not complicated. It just requires consistency — and that consistency compounds into meaningful financial advantages over every carrier who doesn't bother.