Does a Idaho truck need a USDOT number for in-state work?

Yes. Idaho requires a USDOT number for in-state commercial vehicles at 26,001 lb and over (GVWR), even if they never cross a state line.

Checked against Idaho’s official sources in September 2026.

The rule in Idaho

Who it covers: Intrastate carriers hauling in furtherance of their business or for hire, so both private and for-hire. The rule's scope covers carriers transporting persons or property over Idaho highways "in the furtherance of their business or for hire" (IDAPA 11.13.01.001).

The weight line: A truck operating only in Idaho needs an intrastate DOT number at 26,001 lb GVWR or more. Trucks from 10,001 to 26,000 lb follow only a short list of federal safety rules.

Exemptions the state lists:

Carriers exclusively engaged in transporting agricultural commodities (Idaho State Police guidance; the rule text does not define the exception)
Property carriers from 10,001 to 26,000 lb need no intrastate DOT number and follow only 49 CFR 390 Subpart A, 391.15, 392, 393 and parts of 396 (IDAPA 11.13.01.019.01.b)

“Rule 19 of the Idaho Motor Carrier Rules stipulates those vehicles with a GVWR of 26,001 pounds or greater, those with a combination weight rating, those transporting more than 8 passengers, or those hauling hazardous materials requiring placards must obtain an Intrastate DOT number.” source

“Intrastate carriers operating commercial motor vehicles transporting property with a GVW, GVWR, GCW or GCWR greater than ten thousand (10,000) pounds and up to twenty-six thousand (26,000) pounds ... must comply with 49 CFR Part 390 Subpart A, Part 391.15, Parts 392, 393, and Part 396.1” source

The rule: IDAPA 11.13.01.019 (Idaho Motor Carrier Rules, Rule 19); legal authority Idaho Code § 67-2901A

Who to ask: Idaho State Police, Commercial Vehicle Safety

Safety rules for in-state trucks

Idaho adopts by reference 49 CFR Parts 356, 365, 380, 382, 383, 385, 386, 387, 388 and 390-399 for intrastate carriers. Federal exemptions that would otherwise exempt intrastate carriers do not apply, except the § 391.11(b)(1) age rule. (IDAPA 11.13.01.002.04 and 002.05)

Intrastate carriers may hire drivers who are 18 or older.
For 10,001-26,000 lb property carriers, the safety-rule line differs from the DOT-number line. They must follow a short list of federal rules (general definitions, driver disqualification, driving rules, parts and accessories, and some inspection rules) but need no intrastate DOT number.

The federal lines, which apply in Idaho too

10,001 lb and interstate commerce: a USDOT number, a medical card, a driver qualification file, the hours-of-service rules and daily inspections (49 CFR 390.5).
26,001 lb: a CDL, for a single vehicle or a combination towing more than 10,000 lb (383.5). The CDL rules cover in-state driving as well (383.3), and drug and alcohol testing follows the CDL (382.103).

Check your own truck and trailer

Questions

Does Idaho require a USDOT number for intrastate trucks?

Yes. Idaho requires a USDOT number for in-state commercial vehicles at 26,001 lb and over (GVWR), even if they never cross a state line.

What is the CDL weight in Idaho?

The same as everywhere: 26,001 lb for a single vehicle, or a combination of 26,001 lb towing more than 10,000 lb. The federal CDL rules apply to in-state driving too (49 CFR 383.3), and drug and alcohol testing follows the CDL (382.103).

Who administers the rule in Idaho?

Idaho State Police, Commercial Vehicle Safety.

What we could not confirm

The Idaho State Police also list 'those with a combination weight rating' as needing an in-state DOT number without giving a weight, so whether a truck-and-trailer under 26,001 lb needs one is unclear. The rule itself puts combinations of 10,001 to 26,000 lb in the lighter tier.
The rule does not use the words 'DOT number'; the 26,001-lb line for the number is the Idaho State Police's reading of it.

Sources

General information, not legal advice. It summarises Idaho’s published rules as read in September 2026; confirm with the Idaho State Police or FMCSA.