USDOT Number

A USDOT number is the unique identifier the Federal Motor Carrier Safety Administration (FMCSA) assigns to a company when it registers as a motor carrier or other regulated entity. FMCSA uses the number to collect and track the company's safety information, including roadside inspections, crashes, investigations and compliance reviews.

The USDOT number matters because almost every interaction a carrier has with FMCSA and state enforcement is tied to it. If the number is missing from a vehicle, out of date or deactivated, the carrier can face penalties and may be placed out of service.

What Is a USDOT Number?

The USDOT number is assigned once to a company, not to each vehicle or driver. It follows the company through its operating life and links its registration details, such as legal name, address, type of operation, cargo carried, number of power units and drivers, and mileage, to its safety record. Inspectors look up the number during roadside inspections, state-reported crashes are linked to it (carriers also keep their own DOT accident register), and FMCSA uses the data behind it to calculate measures in the CSA Safety Measurement System.

A USDOT number is different from operating authority. Carriers that haul regulated property or passengers for hire across state lines, and brokers and freight forwarders, generally also need operating authority, which FMCSA has historically identified with an MC, FF or MX docket number. FMCSA has proposed making the USDOT number the sole identifier and no longer assigning MC numbers, but that change requires rulemaking and was not part of the first release of its new registration system.

Who Needs a USDOT Number?

Under FMCSA rules, a company needs a USDOT number if it operates commercial motor vehicles in interstate commerce and any of these apply:

• A vehicle has a gross vehicle weight rating or gross combination weight rating, or actual gross weight, of 10,001 pounds or more.
• A vehicle is designed or used to transport more than 8 passengers, including the driver, for compensation.
• A vehicle is designed or used to transport more than 15 passengers, including the driver, not for compensation.
• A vehicle transports hazardous materials in a quantity requiring placards, or materials that require a hazardous materials safety permit.

Intrastate carriers: many states require their intrastate commercial carriers to obtain a USDOT number as well, and intrastate carriers hauling hazardous materials that require a safety permit also need one. Check the rules in each state where you operate.

Vehicle Marking Requirements

Under 49 CFR 390.21, self-propelled CMVs must display the carrier's legal name or a single trade name and the USDOT number, preceded by "USDOT." The marking must appear on both sides of the vehicle, contrast sharply with the background and be readable from 50 feet in daylight while the vehicle is stationary. Rented and leased vehicles have specific marking rules, so confirm which carrier's number should appear.

The Biennial Update (MCS-150)

Every company with a USDOT number must update its registration information every 24 months, even if nothing has changed, under 49 CFR 390.19. This is the biennial update, filed on Form MCS-150 (or MCS-150B for hazardous materials safety permit holders, or MCS-150C for intermodal equipment providers). The schedule is set by the last two digits of the USDOT number:

• Last digit = month. 1 is January, 2 is February, and so on through 9 for September, with 0 for October.
• Next-to-last digit = year. An odd digit means you file in odd-numbered years, and an even digit means even-numbered years.

For example, a USDOT number ending in 47 files every July in even-numbered years. The update is due by the end of the scheduled month.

Where to file: FMCSA has moved registration to a new online system called Motus, which opened to carriers and other registrants in May 2026 and replaced the registration functions of the old FMCSA Portal and Unified Registration System. Motus uses Login.gov identity verification, so allow extra time the first time you file. Check the FMCSA registration pages for current instructions before your filing month.

Deactivation Risks

If a company does not complete its biennial update, FMCSA can deactivate its USDOT number. Operating with a deactivated number can lead to civil penalties, which are adjusted annually for inflation, and to vehicles being stopped at the roadside. A deactivated number must be reactivated by filing an updated MCS-150. Other causes of trouble include outdated contact information, which can mean missing FMCSA notices, and incorrect fleet size or mileage, which can distort safety measures.

How to Keep Your USDOT Number Current Step by Step

1. Confirm you need one. Review your vehicles, passengers, cargo and interstate or intrastate operations against federal and state rules.
2. Register. Apply through FMCSA's current registration system, along with operating authority if your operation requires it.
3. Mark your vehicles. Display the legal or trade name and "USDOT" number on both sides of each power unit as required.
4. Calendar your biennial update. Work out your filing month and year from the last two digits of the number and set reminders well ahead.
5. Gather accurate data. Collect current power unit counts, driver counts, cargo types and annual mileage before filing.
6. Set up system access early. Create and verify the account needed for FMCSA's registration system before the filing deadline.
7. File and keep proof. Submit the update, save confirmation and keep a copy with your company records.

Common Mistakes to Avoid

• Assuming the biennial update is only required when information changes.
• Reporting outdated mileage or fleet size, which affects safety calculations.
• Letting the only person with system access leave the company.
• Using the wrong carrier's number on leased or rented vehicles.
• Ignoring state intrastate registration rules.

How SMS360 Helps

SMS360's DOT Compliance module helps carriers track recurring requirements such as the biennial MCS-150 update with reminders and stored records. Vehicle Management keeps an accurate list of power units for registration filings, and Document Library stores filing confirmations and registration documents.

Frequently Asked Questions

Does a USDOT number expire?

No, but it must be updated every 24 months through the biennial MCS-150 update. If the update is not filed, FMCSA can deactivate the number.

When is my biennial update due?

The last digit of your USDOT number sets the month (1 for January through 9 for September, and 0 for October), and the next-to-last digit sets the year: odd digits file in odd-numbered years and even digits in even-numbered years.

Do intrastate carriers need a USDOT number?

It depends on the state. Many states require intrastate commercial carriers to obtain one, and intrastate carriers transporting hazardous materials that require a safety permit need one under federal rules.

Are MC numbers going away?

FMCSA has proposed making the USDOT number the sole identifier and no longer issuing MC numbers, but this requires rulemaking. Existing MC numbers remain in use until FMCSA finalizes a change.