Texas Transportation Code - TRANSP § 622.074. Nonapplicability of Subchapter

(1) farm equipment used for a purpose other than construction;

(2) special mobile equipment owned by a dealer or distributor;

(3) a vehicle used to propel special mobile equipment that is registered as a farm vehicle under Section 502.433;  or

(4) equipment while being used by a commercial hauler to transport special mobile equipment under hire of a person who derives $500 in gross receipts annually from a farming or ranching enterprise.