Tex. Transp. Code § 551A.053
(a) In addition to the operation authorized by Section 551A.055, the governing body of a municipality may allow an operator to operate an unregistered off-highway vehicle on all or part of a highway that:
(b) In addition to the operation authorized by Section 551A.055, the commissioners court of a county described by Subsection (c) may allow an operator to operate an unregistered off-highway vehicle on all or part of a highway that:
(c) Subsection (b) applies only to a county that:
(3) is adjacent to a county described by Subdivision (2) and:
Added by Acts 2019, 86th Leg., R.S., Ch. 1233 (H.B. 1548), Sec. 31, eff. June 14, 2019.