Okla. Stat. tit. 47, § 47-1133.4: Single or combination farm use vehicle

A. No state agency, unless required under federal law, shall

require any single or combination farm use vehicle included in this

section to participate in the United States Department of

Transportation identification numbering system.

B. For the purposes of this section, single or combination farm

use vehicle is a vehicle or vehicles with a gross combined weight

rating of more than twenty-six thousand one (26,001) pounds if:

1. It is entitled to be registered with a farm tag and has a

farm tag attached thereto;

2. It is controlled and operated by a farmer or rancher, his or

her family or employees;

3. It is used to transport either agricultural products,

livestock, farm machinery, farm supplies or any combination of those

materials to or from a farm;

4. It is not used in the operations of a common or contract

motor carrier; and

5. It is not transporting hazardous materials as defined under

the Oklahoma Motor Carrier Safety and Hazardous Materials

Transportation Act.