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

Yes. Maryland requires a USDOT number for in-state commercial vehicles at 10,001 lb and over (registered weight), even if they never cross a state line.

Checked against Maryland’s official sources in September 2026.

The rule in Maryland

Who it covers: Every truck, truck tractor and bus on Maryland highways (for-hire and private alike) unless exempt. The statute is not limited to for-hire carriers.

The weight line: Trucks registered over 10,000 lb, truck tractors and buses must show a USDOT number or a Maryland-issued intrastate number. Trucks registered at 10,000 lb or less that stay in Maryland are exempt. MDOT SHA says all DOT numbers, including the intrastate MD DOT #, are issued by FMCSA.

Exemptions the state lists:

If operated intrastate only: farm trucks, farm truck tractors and farm area motor vehicles registered as such
Trucks registered at 10,000 pounds capacity or less (intrastate only)
Emergency vehicles
Vehicles used primarily to transport money or commercial paper
Vehicles owned or operated by the State or a political subdivision
Vehicles operating within 15 days from the date of purchase

“If you are a motor carrier who is not required to have a USDOT Number because your vehicles do not leave Maryland and you do not handle interstate cargo, you must obtain a Maryland identification number (MD DOT #) and display it on your trucks, truck tractors and buses.” source

“Maryland law requires that every registered truck over 10,000 pounds, truck tractor and bus operated on public roads, unless specifically exempt*, must display either a USDOT Number or a intrastate motor carrier identification number.” source

The rule: Md. Code, Transp. § 22-404.3 (identification of trucks, truck tractors and buses)

Who to ask: Maryland Department of Transportation State Highway Administration (MDOT SHA), Motor Carrier Division

Safety rules for in-state trucks

Maryland incorporates the FMCSRs (49 CFR 40, 382, 383, 387, 390-393, 384, 395-399 and 1572) by reference, with state amendments and exemptions. The rules apply to trucks and combinations with a GVWR or GCWR of 10,001 lb or more. (COMAR 11.21.01.02 (incorporation) and 11.21.01.03 (application))

The Maryland safety rules apply at a GVWR or GCWR of 10,001 lb or more. That is a rating test, while the USDOT/MD DOT # display law uses registered weight.
Intrastate-only drivers (no placarded hazmat, no 16+ passenger vehicle) may be 18 instead of 21.
The federal medical exam and card requirements do not apply to an intrastate driver of a vehicle with a registered weight under 26,001 lb (no placarded hazmat, no 16+ passenger vehicle).

The federal lines, which apply in Maryland 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 Maryland require a USDOT number for intrastate trucks?

Yes. Maryland requires a USDOT number for in-state commercial vehicles at 10,001 lb and over (registered weight), even if they never cross a state line.

What is the CDL weight in Maryland?

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 Maryland?

Maryland Department of Transportation State Highway Administration (MDOT SHA), Motor Carrier Division.

What we could not confirm

Maryland's statute accepts a USDOT number or a number issued by a state agency, but the State Highway Administration says FMCSA issues every DOT number, including the in-state MD DOT number.
Two provisions in Maryland's rules exempt in-state drivers from the medical exam at different weights (registered under 10,001 lb, and under 26,001 lb); how they fit together was not confirmed.

Sources

General information, not legal advice. It summarises Maryland’s published rules as read in September 2026; confirm with MDOT SHA or FMCSA.