A DOT number is a Department of Transportation number that is required for commercial vehicles. It does not cost anything to get a DOT number but it must be renewed every 2 years. A farm truck's number is basically one that assists in commercial enterprise of agriculture. Some states don't require you to get a DOT number for farm trucks so check your state requirements.
Gather your information. You should be prepared to answer the questions about if your vehicle is considered a commercial vehicle; whether it will be used to transport cargo or passengers across state lines or out of the country; whether the vehicle will transport hazardous material; if you will always be leasing your truck to another company that has a DOT number; how much the truck weighs; how many people it will carry and several other related business questions.
Fill out the form. Go to the DOT website (see "Resources") and click on "Step-By-Step Registration Guide." The guide will ask you all of the questions referenced in the first step and will determine if you need a DOT number.
Apply. You must submit the application and then make sure you comply with your state's regulations. Each state is different and should be researched carefully. (See "Resources" for a link to all of the state level DOTs.)
Larry Amon has been working in the computer field for more than 10 years and has experience writing scripts, instructional articles and political commentary. He has been published online, as well as in "NRB Magazine" and "Delmarva Youth & Family." He started a nonprofit media organization in 2000.