Texas Transportation Code - TRANSP § 647.015. Passenger Seating Requirements for Certain Trips

(1) be securely attached to the vehicle during use;

(2) be not less than 16 or more than 19 inches above the floor;

(3) be at least 13 inches deep;

(4) be equipped with backrests that extend at least 36 inches above the floor;

(5) have at least 24 inches of space between the backrests or the edges of the opposite seats when positioned face to face;

(6) provide at least 18 inches of seat area for each passenger;

(7) not have any cracks that are more than one-fourth inch wide;

(8) not have any cracks in the backrests, if slatted, that are more than two inches wide;  and

(9) have any exposed wood surfaces planed or sanded smooth and free of splinters.