How the engine decides, and how you can check it
Three layers decide every file: federal law, a versioned rulebook and a risk index built on FMCSA SMS mechanics. Below: what is reproduced, what is adapted, the basis for every weight, and tests you can run here.
Clearinghouse prohibited or CDL suspended bars the driver. An expired license or medical certificate, a missing endorsement or a missing required record holds the file for review.
Experience floor, major-violation window, serious-conviction count, crashes not ruled non-preventable, out-of-service orders, recent return-to-duty - each with its own outcome.
The risk index against the rulebook's review and adverse bands. It catches a heavy volume of recent violations that no single rule sees.
Each layer can only raise the outcome. The binding rule is the first rule, in that order, at the final outcome. Engine v2.1.0; the input hash on every record changes if the file, the rulebook, the scale or any what-if changes.
- Recency weights 3 / 2 / 1 for events up to 6 / 12 / 24 months old; older events score zero.
- On the 1-10 scale, +2 severity when a violation put the driver or vehicle out of service.
- The severities one inspection adds to one category are capped at 30 before time weighting, attributed worst-first.
- The enhanced SMS in Federal Register notice 2024-27087: severity 1 or 2, Controlled Substances/Alcohol folded into Unsafe Driving, and Vehicle Maintenance: Driver Observed as its own category.
- Crash weights 1 (tow-away) or 2 (injury or fatality); a crash determined not preventable scores zero.
- Federal bars and holds from 49 CFR 382, 383 and 391, and the 383.51 major / serious offense classes.
- SMS scores carriers against peer groups. Here its mechanics are applied to one driver's file. FMCSA's own Driver SMS is an enforcement tool, not available to carriers; the PSP report is the per-driver record a carrier can use.
- The risk index is round(100 x (1 - e^(-points / N))) with N = 60 on the 1-10 scale and 20 on the 1-2 scale. N is a calibration constant, not fitted to crash or claims outcomes and not an FMCSA percentile.
- The enhanced-SMS mode changes severities and categories but keeps the 3 / 2 / 1 recency weights. FMCSA has not announced when the enhanced SMS goes live.
- A conviction and a roadside violation for the same conduct within a month are treated as one event (scored once, shown with both sources).
- The rulebooks are synthetic examples written for the segment each names; none is a real carrier's or insurer's criteria.
- All driver files and incidents are synthetic. No real person, license or FMCSA query is involved.
The basis for every weight
“SMS table” weights follow FMCSA's published SMS violation severity table for that code; “set here” weights are chosen for this catalog where the code or conviction has no direct SMS weight. The 1-2 column is what the enhanced scale assigns (shown without an out-of-service order).
A state MVR carries convictions and license actions; roadside codes (tires, hours of service, testing) appear only in the PSP inspection history. Rulebooks and their parameters are on the Guidelines page.
Tests that can fail - and are shown failing
Two kinds. The persona contract states, in advance, the outcome a safety director would expect for each sample file and fails if the engine disagrees on either scale. The mutation tests plant one realistic defect at a time and check that the test written for it catches it.
- Line items, categories and total agree
- Same input, same output
- Independent recompute matches the total
- Every what-if matches the independent prediction
- Removing a violation never raises the total
- One inspection adds at most 30 severity per category
- Nothing older than 24 months scores
- Every weight matches the reference catalog
- An event on two records is scored once
- Non-preventable crashes score zero
The expected values come from outside the engine: an independent recompute of the written spec that shares no aggregation code with it, the reference catalogs, and the raw record.
Regulations and figures cited
What a customer deployment adds
MVR vendors, PSP through FMCSA's contractor, Clearinghouse queries with driver consent, CDLIS, and prior-employer 391.23 inquiries, replacing the sample book.
Re-underwrite on every new conviction or license action, and schedule the 391.25 annual review from the record itself.
Fit the index and the bands to the customer's own crash and claims outcomes, and report lift by band before any band is trusted.
SSO and role-based access, a reviewer queue with override reasons, retention to 391.51, and a bias test run on every rulebook change.