FMCSA's Safety Measurement System scores every carrier across seven Behavior Analysis and Safety Improvement Categories, or BASICs. Each one looks at a rolling 24-month window of inspections and crashes, then ranks the carrier against peers of similar size, producing a percentile from 0 to 100. Higher means worse.
What BASICs measure
Unsafe Driving: dangerous or careless operation, like speeding or texting while driving.
Crash Indicator: historical pattern of crash involvement, based on state-reported crash data.
HOS Compliance: hours-of-service violations and driver fatigue management.
Vehicle Maintenance: mechanical defects, load securement, and required repairs.
Controlled Substances/Alcohol: drug and alcohol use, possession, or testing program failures.
HM Compliance: unsafe handling of hazardous materials, like improper placarding or leaking containers.
Driver Fitness: drivers operating without proper licensing, medical qualification, or required files.
What ISS measures
The Inspection Selection System, or ISS, is a separate score built on top of the seven BASICs. It's what a roadside inspector sees when deciding whether to pull a truck in.
A high ISS means specific, addressable issues are on record right now. A low ISS doesn't always mean a clean record. It can just mean there isn't enough inspection data yet to score the carrier.
What's public, and what isn't
The percentile itself is never public, for any of the seven BASICs. Only a carrier logged into its own account, or enforcement, can see the actual percentile number.
What differs between the five behavioral BASICs and the other two is everything else around that percentile.
| Raw data (inspections, violations, crashes) | Calculated measure | Alert / threshold flag | Percentile |
Unsafe Driving, HOS Compliance, Vehicle Maintenance, Controlled Substances/Alcohol, Driver Fitness | Public | Public | Public | Carrier login or enforcement only |
Crash Indicator, HM Compliance | Public | Carrier login or enforcement only | Carrier login or enforcement only | Carrier login or enforcement only |
For the five behavioral BASICs, anyone can see the underlying data, the calculated measure graphed over time, and whether the carrier has crossed its intervention threshold. The only thing withheld is the exact percentile number.
That means a carrier can look completely clean on a public snapshot and still carry a meaningfully different profile once Crash Indicator and HM Compliance are counted in. Neither view is wrong. One of them is just a lot more limited by design.
Why Crash Indicator and HM Compliance are different
Crash Indicator is the only BASIC not built from a specific violation. It measures crash involvement, regardless of fault, unless a crash is submitted through FMCSA's Crash Preventability Determination Program and ruled not preventable.
HM Compliance is violation-based like the public BASICs, but it only scores inspections where the carrier was hauling placardable hazardous materials, a much smaller comparison pool.
How to read a low or missing score
FMCSA requires a minimum amount of inspection data before assigning a percentile at all, typically three or more driver inspections or five or more vehicle inspections. Below that, the field goes blank.
That's not a zero and it's not a passing grade. It means there isn't enough data yet to rank the carrier fairly, and ISS for that carrier will usually resolve low as a default, not as a verified clean record.
Vehicle, driver, and hazmat OOS versus carrier OOS
Vehicle, driver, and hazmat out-of-service orders apply to one unit or driver during a single inspection. Carrier-level OOS means the whole company has been ordered to stop operating.
A carrier can have a high vehicle OOS rate on a handful of inspections and zero carrier-level OOS orders. These are tracked separately and shouldn't be read as the same signal.
Why scores can look different across platforms
Since FMCSA never publishes the percentile itself, any platform showing a percentile for any BASIC, including ISS, is producing an estimate built from public data, not FMCSA's internal number.
That estimate depends on modeling choices FMCSA doesn't publish, like how to build a carrier's peer comparison group for Crash Indicator or HM Compliance. Two platforms working from the same public data can reasonably land on different numbers for the same carrier because there's no single published method to check against, not because either one is wrong.
Timing can also explain a difference. FMCSA refreshes SMS monthly, and a DataQ correction can take time to process. If two platforms pull data on different days relative to that cycle, the same carrier can show slightly different figures for reasons that have nothing to do with methodology at all.
GenLogs calculates all seven BASICs rather than relying on the five that show up in a standard public snapshot, so our view can pick up Crash Indicator and HM Compliance risk that a five-BASIC view won't reflect at all.
If a score looks off or you want to walk through how a specific carrier's ISS was calculated, reach out to us at [email protected].