DOT and MC number lettering: what the rules require
By Nate Burton, Owner
Published
We design, print and install commercial vehicle graphics and wraps in Canton, Ohio: lettering, partial and full wraps for work vehicles, fleets and dealerships. The install studio is in Canton Township, unincorporated Stark County.
This guide quotes the federal and Ohio marking rules; it is general information, not legal advice, so confirm your own obligations with the Federal Motor Carrier Safety Administration (FMCSA) or, for intrastate operation in Ohio, the Public Utilities Commission of Ohio (PUCO).
Which vehicles does the federal marking rule cover?
The federal marking rule is 49 CFR 390.21T, "Marking of self-propelled CMVs and intermodal equipment". It opens: "Every self-propelled CMV subject to this subchapter must be marked as specified in paragraphs (b), (c), and (d) of this section, ..."
You may also see the rule cited as 49 CFR 390.21. Section 390.21 has the same marking requirements but is suspended; section 390.21T carries the text in force.
CMV stands for commercial motor vehicle. Section 390.5T defines it as "any self-propelled or towed motor vehicle used on a highway in interstate commerce to transport passengers or property when the vehicle -" and then lists four tests. Meeting any one of them is enough:
- "Has a gross vehicle weight rating or gross combination weight rating, or gross vehicle weight or gross combination weight, of 4,536 kg (10,001 pounds) or more, whichever is greater"
- "Is designed or used to transport more than 8 passengers (including the driver) for compensation"
- "Is designed or used to transport more than 15 passengers, including the driver, and is not used to transport passengers for compensation"
- "Is used in transporting material found by the Secretary of Transportation to be hazardous under 49 U.S.C. 5103 and transported in a quantity requiring placarding under regulations prescribed by the Secretary under 49 CFR, subtitle B, chapter I, subchapter C"
Source: eCFR, 49 CFR 390.5T, Definitions (current as of September 29, 2026; read October 1, 2026)
Section 390.3T sets out where these federal rules apply, and its paragraph (f) lists exceptions.
Source: eCFR, 49 CFR 390.3T, General applicability (current as of September 29, 2026; read October 1, 2026)
What are the DOT number marking requirements?
Paragraph (b) of 390.21T lists what the marking must display. Paragraph (c), which opens "The marking must", sets where and how it appears, and paragraph (d) how it may be made. Each row below is in the rule's own words.
| Paragraph | The rule's words |
|---|---|
| (b)(1) Name | The legal name or a single trade name of the motor carrier operating the self-propelled CMV, as listed on the motor carrier identification report (Form MCS-150) and submitted in accordance with § 390.19T. |
| (b)(2) USDOT number | The identification number issued by FMCSA to the motor carrier or intermodal equipment provider, preceded by the letters "USDOT." |
| (c)(1) Both sides | Appear on both sides of the self-propelled CMV |
| (c)(2) Contrast | Be in letters that contrast sharply in color with the background on which the letters are placed |
| (c)(3) Legibility | Be readily legible, during daylight hours, from a distance of 50 feet (15.24 meters) while the CMV is stationary |
| (c)(4) Upkeep | Be kept and maintained in a manner that retains the legibility required by paragraph (c)(3) of this section |
| (d) Painted or removable | The marking may be painted on the CMV or may consist of a removable device, if that device meets the identification and legibility requirements of paragraph (c) of this section, and such marking must be maintained as required by paragraph (c)(4) of this section. |
Where another name is on the vehicle, paragraph (b)(3) applies: the operating carrier's name and number must follow the words "operated by".
How big do DOT number letters have to be?
The rule sets a legibility test only and no minimum letter height. Paragraph (c)(3) requires the marking to be "readily legible, during daylight hours, from a distance of 50 feet (15.24 meters) while the CMV is stationary".
Ohio's rules for household-goods carriers set a letter size for the vehicles they use. Ohio Administrative Code 4901:2-19-14(C) reads: "All motor vehicles used to transport household goods in this state shall be marked with the company name, city and state, and PUCO certificate number in letters not less than two inches in height and three-eighths inch in width." It applies to household-goods carriers only, not as a general letter height.
Source: Ohio Administrative Code 4901:2-19-14, Advertisements (effective July 1, 2023; read October 1, 2026)
Do you still need an MC number on the vehicle?
The marking rule lists the carrier's name and USDOT number. No MC number is listed. A carrier may still letter one voluntarily as other identifying information that is not inconsistent with the rule, under paragraph (b)(4).
MC numbers have not been eliminated. FMCSA's registration page reads: "Already have a USDOT Number or docket number? Existing numbers will not change. Motus will continue to issue docket numbers and prefixes (MC/MX/FF) will remain the same." It adds: "Safety Registration, the future elimination of docket numbers, and changes to the BOC-3 form filing process are still under consideration and will be open for public comment in a Notice of Proposed Rulemaking."
Motus is FMCSA's new registration system. Its Federal Register notice of April 29, 2026 says that "the Phase II release of Motus will not include the implementation of safety registration, the elimination of MC/FF numbers, or changes to the Form BOC-3 filing process."
Does anything change for a rented or leased vehicle?
Yes, for a rental or a passenger-carrying lease of 30 calendar days or less. Paragraph (e) of 390.21T reads:
A motor carrier operating a self-propelled CMV under a rental agreement or a passenger-carrying CMV under a lease, when the rental agreement or lease has a term not in excess of 30 calendar days, meets the requirements of this section if: (1) The CMV is marked in accordance with the provisions of paragraphs (b) through (d) of this section; or (2) ...
Under option (2), the vehicle may instead show the lessor's name and USDOT number. The rental agreement or lease must then carry the details the rule sets out and ride in the vehicle for the whole term. Option (2) carries two stated exceptions, in paragraph (e)(2)(v):
Exception. (A) A passenger-carrying CMV operating under the 48-hour emergency exception pursuant to § 390.403(a)(2) of this part does not need to comply with paragraphs (e)(2)(iii) and (iv) of this section, provided the lessor and lessee comply with the requirements of § 390.403(a)(2). (B) A motor carrier operating a self-propelled CMV under a lease subject to subpart G of this part (§§ 390.401 and 390.403) must begin complying with this paragraph (e) on January 1, 2021.
For property-carrying equipment a for-hire carrier takes on under a lease subject to 49 CFR part 376, section 376.11(c)(1) reads: "During the period of the lease, the carrier shall identify the equipment in accordance with the FMCSA's requirements in 49 CFR part 390 of this chapter (Identification of Vehicles)."
What changes for carriers operating within Ohio?
Ohio adopts the federal rules, marking included, for intrastate carriers, and then changes the marking rule. Ohio Administrative Code 4901:2-5-03(B) reads: "All motor carriers operating in intrastate commerce are subject to the provisions of this chapter and the regulations adopted pursuant to paragraph (A) of this rule."
The changes are in rule 4901:2-5-10(A):
(1) The identification number issued by the commission preceded by the letters PUCO may be displayed in lieu of a U.S. department of transportation (USDOT) number.
(2) Private motor carriers operating in intrastate commerce are not required to display a USDOT or PUCO number.
For intrastate carriers, "commercial motor vehicle" follows the 49 CFR 390.5 definition for for-hire carriers and the 49 CFR 383.5 definition for private carriers, under rule 4901:2-5-01(B).
Source: Ohio Administrative Code 4901:2-5-01, Definitions (effective October 30, 2014; read October 1, 2026)
Source: eCFR, 49 CFR 383.5, Definitions (current as of September 29, 2026; read October 1, 2026)
Ohio's rules cite the federal sections by their suspended numbers, 390.21 and 390.5, as effective August 1, 2025, under rule 4901:2-5-02(C). Compared with 390.21T and 390.5T on eCFR, the marking requirements are the same, and the CMV definitions in 390.5 and 390.5T are identical.
How do we letter USDOT and MC numbers?
USDOT and MC numbers are lettered to spec. Our guide Vehicle lettering, partial wrap or full wrap: what each one covers sets out the three packages.
Our production page lists "Your USDOT or MC number if you display one" among what we need from you. Our guide Artwork files for vehicle graphics: what to send sets out the artwork files and the rest of that list.
Our box truck and trailer wraps page sets out lettering, partial wraps and full wraps for box trucks, and for trailers up to 53 feet.
How do you get a quote?
Request a quote. Five short steps: your vehicle, the package, project details, artwork, and how to reach you. We confirm scope and price within one business day.
Our guide What it costs to letter or wrap a work vehicle in Canton, Ohio sets out what changes the price.
Call or text (330) 775-0998.
Questions
What does a DOT number marking have to show?
Under 49 CFR 390.21T, the marking on a commercial motor vehicle the rule covers must display the legal name or a single trade name of the motor carrier operating it, as listed on its Form MCS-150, and the identification number FMCSA issued to that carrier, preceded by the letters "USDOT". If another name is on the vehicle, the operating carrier's name and number must follow the words "operated by".
How big do DOT number letters have to be?
The federal marking rule, 49 CFR 390.21T, sets a legibility test only and no minimum letter height. The marking must appear on both sides of the vehicle in letters that contrast sharply in color with the background, be readily legible, during daylight hours, from a distance of 50 feet while the vehicle is stationary, and be kept legible.
Do you still need an MC number on your truck?
The federal marking rule, 49 CFR 390.21T, lists the carrier's name and USDOT number and no MC number; a carrier may still letter one voluntarily as other identifying information that is not inconsistent with the rule. MC numbers have not been eliminated: FMCSA's registration page, read September 30, 2026, says existing numbers will not change and docket number prefixes (MC/MX/FF) will remain the same.
Does Ohio accept a PUCO number instead of a USDOT number?
For intrastate carriers, Ohio Administrative Code 4901:2-5-10(A) reads: "The identification number issued by the commission preceded by the letters PUCO may be displayed in lieu of a U.S. department of transportation (USDOT) number." It adds: "Private motor carriers operating in intrastate commerce are not required to display a USDOT or PUCO number."
Do you letter USDOT and MC numbers?
Yes. USDOT and MC numbers are lettered to spec.