How to Read an SMS Percentile

A percentile is meant to answer a simple question: compared to its peers, how does this carrier rank? A BASIC percentile of 80 would mean a carrier's calculated measure for that category is worse than 80% of comparable carriers — a useful shorthand, if you know exactly what "comparable carriers" means and where the number actually came from. That second part is where most confusion starts, because FMCSA doesn't publish an official percentile for every type of carrier.

What FMCSA actually publishes, by carrier type

FMCSA's Safety Measurement System (SMS) splits carriers into separate public datasets by the kind of operation they run. For property carriers — the trucking companies that haul freight, which make up the overwhelming majority of active carriers — the published dataset includes a raw calculated measure for each BASIC and a Y/N alert flag showing whether FMCSA considers that measure high enough to warrant attention. It does not include an official percentile ranking.

For the much smaller group of bus and hazmat-passenger carriers, FMCSA's published dataset does include an official percentile, alongside the measure and alert flag. So depending on which kind of carrier you're looking at, the same word — "percentile" — can mean either "an FMCSA-calculated ranking" or "not published by FMCSA at all," and getting that distinction backwards leads people to either trust a number that doesn't exist or dismiss one that's actually official.

How CarrierPedia fills the gap

Because a raw measure on its own is hard to interpret — is 0.6 high or low for Unsafe Driving? — CarrierPedia computes its own percentile for property carriers, ranking each carrier's FMCSA-published measure against every other active property carrier in our database for that same BASIC. This is clearly labeled wherever it appears as a CarrierPedia-computed percentile, distinct from an official FMCSA figure, because it uses a different peer group and methodology than FMCSA's own (unpublished, for this carrier type) internal calculation. The alert flag shown alongside it, however, is always FMCSA's original value — we never calculate that ourselves.

This distinction matters if you're comparing a CarrierPedia profile to something else you've seen — a report from a compliance vendor, for instance, might use a different peer group or a different lookback window and land on a different percentile for the same underlying measure. None of these are "wrong" exactly; they're answering the ranking question with different comparison sets. See Data Sources for exactly which FMCSA dataset each figure on this site comes from.

Reading a percentile in context

A single percentile is more useful alongside a few other pieces of information: how many inspections the underlying measure is based on (a measure calculated from three inspections carries a lot less statistical weight than one from thirty), whether the carrier has an active alert flag in that BASIC, and how that percentile compares to the same carrier's percentile in the other four categories. A carrier flagged in one BASIC but unremarkable in the other four tells a different story than one elevated across the board.

When there's no percentile at all

Some carriers don't have enough recent inspection activity for FMCSA to calculate a reliable measure in a given BASIC, let alone a percentile. In that case, a CarrierPedia profile shows the inspection count and explains that FMCSA hasn't published enough data for that category, rather than showing a blank chart or guessing at a number. This is a data limitation, not a red flag — plenty of well-run carriers simply haven't had enough recent inspections to generate a statistically meaningful score.

Putting it together

See What the Five FMCSA BASICs Actually Measure for what each category tracks, and Safety Rating Lookup to check a specific carrier's current BASIC results and whether it has enough data for a full picture in each category.