USDOT number display guide
USDOT Number Display Regulations: Location, Lettering and State Requirements
Before you put a commercial vehicle into service, make sure your legal business name and USDOT number are easy to read on both sides of the power unit. Here is the federal rule, a practical sizing guide, and direct links to motor-carrier information for every state.
Reviewed and updated July 15, 2026
The quick answer
Federal regulation 49 CFR § 390.21 requires the motor carrier's legal name or a single trade name and the USDOT number to be marked on both sides of the self-propelled commercial motor vehicle. The marking must contrast sharply with the background, be maintained so it stays legible, and be readable in daylight from 50 feet while the vehicle is stationary.
The federal rule does not set a universal two-inch minimum letter height. We recommend letters at least 2 inches tall for most trucks because that is a practical way to help meet the 50-foot visibility requirement. Go larger when space allows. Some states, cities, operating authorities, or vehicle types may require additional markings or a specific size.
USDOT number display checklist
- Both sides: Mark both sides of the power unit. The cab or vehicle doors are the most common locations.
- Correct name: Use the legal name or one trade name shown in your FMCSA record.
- Correct format: Show the identification number preceded by “USDOT,” for example: USDOT 1234567.
- High contrast: Use bold lettering that contrasts sharply with the paint or background.
- Readable at 50 feet: The markings must be legible in daylight from 50 feet when the vehicle is stationary.
- Keep it readable: Replace lettering that is peeling, faded, damaged, covered by dirt, or blocked by equipment.
- Check local rules: Intrastate carriers and carriers operating under special state or local authority may need extra numbers, names, weights, or markings.
Vinyl lettering or magnetic signs?
Vinyl USDOT decals
Best for permanent vehicles and fleets. Properly applied vinyl has a clean, painted-on appearance and stays in place through normal highway use.
Shop USDOT decalsMagnetic USDOT signs
A good choice for temporary use, leased vehicles, or trucks used for more than one purpose. Apply only to a clean, flat, steel surface and check the sign before every trip.
Shop USDOT magnetsWe recommend going as large as possible while remaining aesthetically pleasing. Larger, bold lettering gives you more visibility and helps avoid questions during an inspection.
USDOT and commercial vehicle rules by state
Federal rules apply to interstate motor carriers, but a state may also require a USDOT number for intrastate operations or require additional vehicle markings. Select the state where your company is based and check any state where you regularly operate. These links lead to official state or federal motor-carrier resources.
Government websites occasionally move pages. If a link has changed, start at the agency homepage or use the FMCSA state contact directory.
Who needs a USDOT number?
In general, a company operating in interstate commerce needs a USDOT number when it uses a vehicle with a GVWR, GCWR, GVW, or GCW of 10,001 pounds or more; transports more than eight passengers for compensation; transports 16 or more passengers including the driver; or transports certain quantities of hazardous materials. Many states also require a USDOT number for some intrastate carriers.
Use FMCSA's official “Do I Need a USDOT Number?” guide. There is no charge to obtain a USDOT number directly from FMCSA.
Useful carrier tools
Look up a USDOT number
Use the free FMCSA SAFER Company Snapshot to check a carrier's name, USDOT number, operating status, and public safety information.
Open SAFER Company SnapshotRegister or update your record
Use the official FMCSA registration site for current application and update instructions. Avoid websites that imply there is a government fee for the USDOT number itself.
Visit FMCSA RegistrationHazardous materials
USDOT identification lettering is separate from hazardous-material package marks, labels, and vehicle placards.
View the FMCSA placarding guideUSDOT number display questions
How tall do USDOT numbers have to be?
The federal rule requires the marking to be readable in daylight from 50 feet while the vehicle is stationary; it does not establish a universal two-inch minimum. We recommend lettering at least 2 inches tall for most trucks, with larger letters when the available space and viewing conditions call for them. Always check state and local rules.
Where should I put my USDOT number?
Display it on both sides of the self-propelled commercial motor vehicle. The cab doors are the most common location because they are flat, visible, and easy to keep clean.
Does the company name have to be displayed too?
Yes. The federal marking must show the legal name or a single trade name of the motor carrier as listed in the FMCSA record, along with the USDOT number.
Can I use magnetic USDOT signs?
Yes, provided the signs meet the same content, contrast, placement, visibility, and maintenance requirements. Make sure the surface is steel, clean, flat, and suitable for a magnet. Check that each sign is secure before driving.
Do I need an MC number on the truck?
FMCSA no longer requires most carriers to display an MC number on the vehicle under the federal marking rule. Other state, local, contract, or operating-authority markings may still apply.
Do rented or leased commercial vehicles need markings?
Yes, when the vehicle is operating as a regulated commercial motor vehicle. The exact marking can depend on the lease arrangement and exceptions in 49 CFR § 390.21, so review the rule and your operating agreement.
Official sources
- 49 CFR § 390.21 — Marking of self-propelled CMVs and intermodal equipment
- FMCSA — Do I Need a USDOT Number?
- FMCSA Registration
- FMCSA SAFER Company Snapshot
Important: This page is a general guide, not legal advice. Regulations change, and the correct markings depend on the vehicle, cargo, operating authority, and where you operate. Confirm current requirements with FMCSA and the appropriate state or local agency.