CSA Scores Explained: The Seven BASICs, the Percentiles, and What You Can Actually See

CSA stands for Compliance, Safety, Accountability. Its scoring engine is the Safety Measurement System (SMS), which takes violations from roadside inspections, crash reports from roughly the last two years, and investigation results, and sorts them into behavioral categories called BASICs — Behavior Analysis and Safety Improvement Categories.

The reason CSA matters to a broker is coverage. A formal safety rating requires a compliance review, and around 92 to 94% of interstate carriers have never had one. Roadside data accumulates on its own every time a truck is inspected, so CSA gives you a recent, behavior-based read on carriers that would otherwise be a complete blank.

It is a relative measure, not an absolute one. A carrier is scored against a peer group of carriers with a similar volume of safety events, then expressed as a percentile within that group. It answers "how does this carrier compare to similar carriers" — not "is this carrier safe."

• Unsafe Driving. Speeding, reckless driving, improper lane changes, texting — how the truck is actually operated on the road.
• Hours-of-Service Compliance. Driving beyond legal limits and logbook or ELD violations. A proxy for fatigue risk and for whether dispatch pressures drivers.
• Driver Fitness. Licensing, medical certification, and driver qualification files — whether the person driving is properly qualified to be there.
• Controlled Substances / Alcohol. Impairment violations and testing-program failures. Low volume, high severity.
• Vehicle Maintenance. Brakes, tires, lights, steering, cargo securement. Usually the highest-violation category, because equipment defects are the most common finding at roadside.
• Hazardous Materials Compliance. HM placarding, packaging, and handling. Only applies to carriers hauling hazardous materials — and not publicly visible.
• Crash Indicator. Crash history weighted by severity and recency. Also not publicly visible.

Five are public in SMS. Crash Indicator and Hazardous Materials Compliance are restricted — visible to the carrier itself when logged into its own profile, and to enforcement, but not to you. Public visibility of percentile data was narrowed by a congressional mandate in the 2015 FAST Act, which is why what a broker can see today is less than what the system holds.

This is the single most common misreading. CSA percentiles run 0 to 100 and a higher number is worse. A carrier at 80 in Unsafe Driving is not scoring 80% well — it is in the worst 20% of its peer group for that behavior. People see a number near 100 and read it like a grade. It is closer to a rank of how far toward the bad end of the field the carrier sits.

• Peer groups make the number relative. A carrier is compared against others with a similar number of safety events, not against the entire industry. A percentile is a position within that cohort, so the same raw violation history can land differently depending on the peer group.
• Not every carrier has a score in every BASIC. A BASIC only gets a percentile once there is enough data. A blank is not a zero and it is not clean — it means too little was measured to rank the carrier at all.
• Thin data swings hard. A carrier with a handful of inspections can post an alarming percentile off one bad stop. Always look at how many inspections sit behind the number before reacting to it.
• Recent violations weigh more. SMS weights events by how recently they happened, so scores drift down over time as old violations age out. A high score means recent behavior, not ancient history.

CSA is a useful signal and a poor verdict. It describes measured behavior in specific categories; it does not tell you whether a carrier is properly insured, holds valid authority, or is who it claims to be over email. Those are separate checks, and they catch different failures.

• Read the pattern, not the worst number. High Vehicle Maintenance with clean Unsafe Driving points at a maintenance program, not driving culture. The distribution across BASICs tells you what to ask about.
• Cross-check against out-of-service rates. OOS rates are drawn from the same roadside stream and are directly comparable to a published national average, which makes them an easier sanity check on whether a percentile reflects real volume.
• Do not treat a blank as a pass. The same discipline as safety ratings applies. No score means not measured. A new authority with no inspection history has no CSA profile, and that is its own risk category rather than a clean one.
• It says nothing about identity. CSA scores describe the carrier on the federal record. They cannot tell you whether the person emailing you a rate confirmation is actually that carrier — impersonation passes every entity-level safety check ever devised.
• Document what you looked at. Whatever you conclude, the dated record of having checked is what demonstrates a considered selection if the load is ever litigated.