Tex. Loc. Gov't Code § 342.013
(b) It is an affirmative defense to prosecution for possession of fireworks brought under a municipal ordinance that:
(c) For purposes of Subsection (b), the "passenger area" of a motor vehicle means the area of the vehicle designed for the seating of the operator and the passengers of the vehicle. The term does not include:
Added by Acts 2013, 83rd Leg., R.S., Ch. 957 (H.B. 1813), Sec. 2, eff. June 14, 2013.