What is an ISS score?
ISS is the federal Inspection Selection System, a score and band that tells roadside enforcement whether to inspect a truck. What the three bands mean.
ISS stands for Inspection Selection System. It is a federal algorithm that turns a motor carrier's safety data into a score from 1 to 100 and one of three recommendations, shown to roadside enforcement when a truck's USDOT is queried at a weigh station or checkpoint. The three bands are Inspect, Optional and Pass.
A higher score means more inspection attention, not better performance. This is the opposite of most scores and catches people out.
#The three bands
| Band | Roughly means |
|---|---|
| Inspect | Enough adverse safety data to warrant an inspection |
| Optional | Mixed or insufficient data; the inspector decides |
| Pass | The data does not warrant an inspection now |
An Optional result frequently means not enough data, not middling performance. A brand-new carrier with almost no inspection history often sits here for that reason.
#Why an insurance agent cares
Two reasons, one obvious and one less so.
The obvious one: ISS is built from the same underlying safety data underwriters look at. A carrier in the Inspect band has a safety record that is bad enough for the federal government to prioritise pulling its trucks in.
The less obvious one: the band is self-reinforcing. A carrier in Inspect gets inspected more, which produces more violations, which keeps it in Inspect. That matters for a carrier trying to improve: the climb out is slower than the fall in, and a carrier that has genuinely fixed its operation can carry the band for a while afterwards. It also matters commercially: more inspections means more time out of service, which the insured feels as lost revenue before it ever shows up as a claim.
#What ISS is not
- Not a safety rating. The federal safety rating (Satisfactory, Conditional, Unsatisfactory) is a separate thing, assigned after a compliance review. A carrier can be Satisfactory and sit in Inspect.
- Not a credit-style score. There is no reward for a long clean history the way there is in credit. It reads recent data.
- Not stable. It moves as inspections and violations age in and out.
#Official versus estimated
The score enforcement sees is generated by the federal system. The algorithm itself is published, and the safety data it runs on is public, so an ISS result can be reconstructed from public data by anyone who implements the published method.
That distinction matters when you see an ISS figure outside a government system:
- The band (Inspect, Optional, Pass) is generally reliable when reconstructed, because the band boundaries are coarse.
- The 1–100 number should be treated as directional. It is an estimate of an official value, not the official value.
Native Base Market Tracker shows an estimate on this basis and labels it as one. If you want to check a single carrier, the ISS score checker does it from a USDOT number for free.
#Using it in underwriting
ISS is a good triage signal and a poor sole criterion. It compresses a lot of detail into one number, and the detail is where the underwriting sits.
A sensible order: read the band first as a sorting mechanism, then go to the BASIC percentiles to find out why the band is what it is. An Inspect band driven by Vehicle Maintenance on a heavily-inspected fleet is a different risk from an Inspect band driven by Unsafe Driving and crashes.
#Related
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