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DOT numbers: Intrastate commercial vehicles

The U.S. Department of Transportation number (DOT number) is used to track the safety fitness rating of commercial vehicles and their owners.

Types of vehicles that must have a DOT number

If you operate any of the following commercial vehicles within Washington State, you must get a DOT number and display it on the vehicle:

  • Commercial motor vehicles with Gross Vehicle Weight Rating (GVWR) of 16,001 pounds or more.
  • Combinations of commercial motor vehicles including a towed unit with a GVWR of 10,000 pounds or more and having a total GVWR of 16,001 pounds or more.
  • Commercial motor vehicles of any size used in the transportation of placarded hazardous materials.
  • Commercial motor vehicles designed to transport 16 or more passengers, including the driver.
  • Private school buses of any weight or size.

Farm vehicles

Farm vehicles must have an intrastate DOT number, but they are exempt from safety audits and compliance reviews. Commercial motor vehicles owned and operated by farmers must have a DOT number if they are:

  • One of the types of vehicles described above.
  • and
  • Used to transport the farmer's own orchard, farm, or dairy products, livestock, or plant/animal waste within Washington State.

(Note: To learn how to find the GVWR for your vehicle, see Gross Vehicle Weight Rating (GVWR) below.)

What to do when you register your vehicle

Use the DOT Number Determination/Disclosure form to determine if you need a DOT number and provide the information needed to register the vehicle.

  1. First, answer the questions at the top of the form to see if the vehicle needs a DOT number.
  2. If it does, complete the rest of the form and include it with your registration application or renewal.

How to apply for a DOT number


There is no charge to get a DOT number.

Gross Vehicle Weight Rating (GVWR)

The Gross Vehicle Weight Rating (GVWR) of a commercial vehicle is:

  • For a single vehicle, the value specified by the vehicle manufacturer as the maximum loaded weight of the vehicle.
  • For a combination of vehicles, the value specified by the vehicle manufacturer as the maximum loaded weight of the towing unit plus the GVWR of the towed unit or units.

Example showing location of GVWR on commercial vehicle label.Finding your vehicle's GVWR

The GVWR can be found in several places:

  • A label on the inside frame of the driver's door.
  • In the engine compartment.
  • In the vehicle owner's manual or sales brochure.

For trailers, you may find a label towards the front of the trailer on the left side.

If you can't find the GVWR

If you can't find your vehicle's GVWR, call the Washington State Patrol at 360.596.3810.

How DOT numbers improve safety

The DOT number will be used to track citations for unsafe vehicles, traffic violations, and accidents. The data collected will be used to establish safety ratings that the Washington State Patrol will use to perform compliance reviews on businesses identified as higher risk. If a review is unsatisfactory, the DOT number will be placed out of service and all the registrations for vehicles listed under that number will be canceled.

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