The FMCSA's Compliance, Safety, Accountability (CSA) program is the federal government's primary system for identifying high-risk motor carriers. It processes data from roadside inspections, crash reports, and compliance investigations to produce scores across seven safety categories.

If you ship freight and you've never looked at a carrier's CSA scores, you're making decisions without the most relevant data available. Here's how to read them.

The Seven BASIC Categories

CSA scores are organized into seven Behavior Analysis and Safety Improvement Categories, called BASICs. Each one measures a different aspect of carrier safety:

1. Unsafe Driving Covers moving violations observed during roadside inspections: speeding, reckless driving, improper lane changes, texting while driving, failure to wear a seatbelt. This is the most directly predictive category for crash risk.

2. Hours of Service Compliance Tracks violations related to driver fatigue rules: exceeding maximum driving hours, falsifying logs, failing to take required rest breaks. Fatigued driving is a factor in roughly 13% of large truck crashes.

3. Driver Fitness Measures whether drivers are properly licensed, medically certified, and qualified to operate the vehicle they're driving. Violations include expired medical certificates, operating without a valid CDL, and driving outside of license restrictions.

4. Controlled Substances / Alcohol Tracks violations related to drug and alcohol use: testing positive, refusing a test, possession of controlled substances. This category has the lowest violation rate but the highest severity.

5. Vehicle Maintenance Covers mechanical violations found during vehicle inspections: brake defects, tire problems, lighting issues, cargo securement failures. High vehicle maintenance scores strongly correlate with higher crash rates.

6. Hazardous Materials Compliance Only applies to carriers that transport hazmat. Measures compliance with hazmat handling, labeling, placarding, and documentation requirements.

7. Crash Indicator Based on crash reports from the past 24 months, weighted by severity. This isn't a measure of fault — it includes all reportable crashes regardless of who caused them.

How Percentiles Work

CSA scores are expressed as percentiles from 0 to 100. This is where most people get confused.

Higher percentile = worse performance. A carrier at the 80th percentile has more violations per inspection than 80% of comparable carriers in that category. Think of it like a ranking where you don't want to be at the top.

The FMCSA compares carriers against peers with similar inspection counts and cargo types, so a small local carrier isn't directly compared against a 10,000-truck fleet.

Intervention Thresholds

The FMCSA sets intervention thresholds that trigger regulatory action:

BASIC Category	Threshold	Hazmat Threshold
Unsafe Driving	65th percentile	60th
Hours of Service	65th	60th
Driver Fitness	80th	80th
Controlled Substances	80th	80th
Vehicle Maintenance	80th	75th
Hazmat Compliance	80th	80th
Crash Indicator	65th	60th

Carriers above these thresholds may receive warning letters, targeted inspections, or compliance investigations. But "may" does the heavy lifting in that sentence. Many carriers operate above intervention thresholds for months or years without consequence.

What CSA Scores Don't Tell You

CSA scores have real limitations that shippers should understand:

Inspection bias. Carriers that operate in states with higher inspection rates accumulate more data points. A carrier based in Texas gets inspected more often than one in Wyoming, which means their scores reflect more data — for better or worse.

No fault in crash data. The Crash Indicator includes all reportable crashes, whether the carrier was at fault or not. A carrier rear-ended at a traffic light counts the same as one that caused a rollover.

Time decay. Violations are weighted by recency — recent violations count more than older ones. But the lookback window is 24 months, so a single bad quarter can inflate scores for two years.

Small carrier data gaps. Carriers with fewer than three inspections in a category don't receive a score for that BASIC. Small carriers can fly under the radar.

How Shippers Should Use This Data

CSA scores are a screening tool, not a verdict. Here's a practical approach:

Check all seven BASICs. Don't just look at one category. A carrier with clean Unsafe Driving scores but terrible Vehicle Maintenance still has structural problems.
Compare against thresholds. Any carrier above the intervention threshold in any category warrants closer scrutiny. Multiple categories above threshold is a serious red flag.
Look at trends. A carrier whose scores are rising has a deteriorating safety culture. A carrier whose scores are falling is investing in improvement. Direction matters as much as position.
Check out-of-service rates. OOS rates tell you what happens when an inspector looks at the actual truck and driver. High OOS rates — especially vehicle OOS above 25% — indicate maintenance problems that CSA percentiles might not fully capture.
Verify insurance. CSA scores won't help you if the carrier's insurance has lapsed. Check BIPD and cargo insurance status separately.

No single metric tells the full story. But CSA scores are the closest thing to a standardized safety rating that exists for motor carriers, and ignoring them is a risk most shippers can't afford.