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Idaho truck lettering requirements
Short answerWhat applies for certain in Idaho is the federal rule, 49 CFR 390.21: your legal name or a single trade name and your USDOT number on both sides of the power unit, in a color that contrasts with the paint and legible from 50 feet in daylight. FMCSA's lists show Idaho also requires it of intrastate carriers from 26,001 lbs up. Agency note: Name and USDOT 2 inch reported. We are confirming the state statute text; until then, letter to the federal rule and ask the state agency if you only operate in-state.
Some details on this page come from agency guidance rather than the statute text and are being confirmed. The federal rule below applies regardless.
What Idaho requires
| USDOT for intrastate carriers | Yes, for vehicles of 26,001 lbs and up used in commerce inside the state, per FMCSA's lists. |
|---|---|
| State number | Name and USDOT 2 inch reported |
| Printed format | Name and USDOT 1234567 |
| Size | See the rule above; Idaho sets a real minimum. |
| Enforced by | Idaho state police / commercial vehicle enforcement; state DOT |
| Sources | 49 CFR 390.21; FMCSA intrastate registration lists; state agency guidance (being confirmed) |
What the door looks like
Your Company LLC
USDOT 1234567
Also worth knowing
- Two inch numbers with the name a little larger pass the 50 foot test in every state.
- The MC number is not a marking requirement anywhere; add it if you want brokers to see it.
The federal rule underneath
49 CFR 390.21 applies to every commercial motor vehicle in interstate commerce: legal or single trade name, the letters USDOT and the number, both sides of the power unit, contrasting color, legible from 50 feet in daylight while parked. No federal inch minimum. The MC number is not a federal marking requirement, and trailers don't need markings. States add to this; they don't replace it.
Checked September 2026. Plain-English summary of the regulations, not legal advice. Rules change; the citations above are where to confirm.