The federal test, both halves
FMCSA requires a USDOT number when a vehicle meets one of the size or use thresholds and is involved in interstate commerce. People usually get this right on the vehicle and wrong on the commerce half, so take them separately.
Half one: the vehicle
Any one of these is enough:
- A gross vehicle weight rating or gross combination weight rating, or actual gross vehicle or combination weight, of 10,001 pounds or more, whichever is greater.
- Designed or used to transport more than 8 passengers including the driver, for compensation.
- Designed or used to transport more than 15 passengers including the driver, when not for compensation.
The two passenger thresholds are commonly reported as one number, and they are not. Whether money changes hands moves the line from 15 to 8.
Half two: interstate commerce
This is the half that surprises people, because it is about the freight, not the truck. Interstate commerce includes trade, traffic, or transportation between a place in a state and a place outside it, between two places in a state by way of another state, and, critically, between two places in the same state as part of trade that originates or terminates outside that state.
That last clause catches a lot of local operations. If you haul a container from a port to a warehouse forty miles away, and that container came from overseas or is bound out of state, your truck never left the state but the freight is in interstate commerce. Drayage, final-mile from an out-of-state distribution center, and hauling for a shipper whose goods are moving across state lines can all land here.
The hazmat exception, which needs no interstate half
If you carry the types and quantities of hazardous materials that require a safety permit, you need a USDOT number even operating purely within one state. See 49 CFR 385.403 for the permit thresholds. This is the one route to a federal number that does not require crossing a state line or hauling interstate freight.
The state list nobody mentions
Separately from the federal rule, many states require their own intrastate commercial registrants to carry a USDOT number. By FMCSA's own count that is 38 states plus Puerto Rico. The list includes most of the large freight states: California, Texas, Florida, New York, Pennsylvania, Ohio, Georgia, Michigan, Washington, and many more.
So the honest answer to "I only run inside my state, am I exempt" is usually no, and for a different reason than the federal one. Check with your state agency, because the state sets its own thresholds and they are not always the federal ones.
What it costs, and what it does not
FMCSA publishes its fee schedule at 49 CFR 360.3T. Two lines from it are worth knowing by heart, because they are the ones most often misrepresented:
- Biennial update of registration: $0. Your MCS-150 update is free, forever, at the official portal. Anyone charging you for it is charging for typing.
- Application for USDOT registration: $300. This is the operating authority application, a real government fee that genuinely costs money.
Changes of name or address, cancellation, and designating a process agent are all listed at $0. Reinstatement is $10. If a letter quotes you a different figure for any of these, compare it against the schedule before paying, and see our guide to spotting a fake compliance letter.
USDOT number and MC number are not the same thing
A USDOT number identifies your company for safety: inspections, crashes, audits, and your public record all hang off it. Operating authority, the MC number, is separate permission to haul regulated commodities for hire. Many carriers need both, some need only the USDOT number, and the two are not interchangeable when a form asks for one specifically.
Once you have one
The number itself is not the end of it. It has to be kept current: the MCS-150 biennial update is due on a schedule derived from the digits of your own number, FMCSA sends no reminder, and letting it lapse can deactivate the number. Our due date calculator works that out from your USDOT number in the browser, and the biennial update guide explains the rule behind it.