Tex. Civ. Prac. & Rem. Code § 72.001

A person who is related to the owner or operator of a motor vehicle within the second degree by consanguinity or affinity, as determined under Chapter 573, Government Code, and who is being transported in the motor vehicle over a public highway of this state as a guest without payment for the transportation has a cause of action against the owner or operator of the motor vehicle for injury, death, or loss in a collision only if the collision was intentional on the part of the owner or operator or was caused by the owner's or operator's heedlessness or reckless disregard of the rights of others.