(a) A road tractor, truck, trailer, truck-tractor in combination with a semitrailer, or semitrailer in combination with a towing vehicle that has at least four tires or at least two super single tires on the rearmost axle of the vehicle or the rearmost vehicle in the combination shall be equipped with safety guards or flaps that:(1) are of a type prescribed by the department; and(2) are located and suspended behind the rearmost wheels of the vehicle or the rearmost vehicle in the combination within eight inches of the surface of the highway.(b) This section does not apply to a truck-tractor operated alone or a pole trailer.(c) In this section, 'super single tire' means a wide-base, single tire that may be used in place of two standard tires on the same axle. Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.Amended by: Acts 2011, 82nd Leg., R.S., Ch. 752 (H.B. 1330), Sec. 1, eff. September 1, 2011.