1991 Thomas Built HDX
Decoded identity
From the 17-character VIN via NHTSA vPIC
- VIN
- 1T7Y84F20M1167635
- Make
- Thomas Built
- Model
- HDX
- Model year
- 1991
- Body class
- Bus - School Bus
- Vehicle type
- BUS
- GVWR
- Not decoded
- Decoded at
- Jun 28, 2026
Decode evidence & sources
Deterministic structure
These fields come directly from VIN positions and the published checksum calculation, with zero store IO.
Position 10 repeats every 30 years; both candidates are retained and neither is silently selected.
Deterministic · positions 12–17 for a North American WMI.
Sourced platform inference
The prefix store publishes only at support ≥ 3 and purity ≥ 90%. Prefix confidence is shown beside every established platform claim.
Prefix basis · 435 decoded VINs at 100.0% prefix purity.
Prefix basis · 435 decoded VINs at 100.0% prefix purity.
No sourced model-line label is established.
No source established for this field.
No sourced generation label is established.
No source established for this field.
No sourced cab label is established.
No source established for this field.
Federal observation (NHTSA vPIC)
What the federal corpus observed directly for this exact VIN — independent of, and sometimes more specific than, the prefix-level inference above.
Observed directly for this VIN via NHTSA vPIC.
Observed directly for this VIN via NHTSA vPIC.
Observed directly for this VIN via NHTSA vPIC.
Observed directly for this VIN via NHTSA vPIC.
Observed directly for this VIN via NHTSA vPIC.
Observed directly for this VIN via NHTSA vPIC.
Not established
- model line
- generation
- cab type
These are withheld claims, not negative findings.
Inspection history
Every roadside inspection of this VIN, newest first · Apr 24, 2024 – Jul 21, 2026
Carriers this unit has run under
2 distinct carriers · grouped by DOT · newest activity first
Plate & unit-number history
The same truck under different plate registrations across carriers