(a) Except as provided by Subsection (b), a permit issued under § 623.011 does not authorize the operation of a vehicle on:
(1) the national system of interstate and defense highways in this state if the weight of the vehicle is greater than authorized by federal law; or
(2) a bridge for which a maximum weight and load limit has been established and posted by the Texas Transportation Commission under § 621.102 or the commissioners court of a county under § 621.301, if the gross weight of the vehicle and load or the axles and wheel loads are greater than the limits established and posted under those sections.
(b) The restrictions under Subsection (a)(2) do not apply if a bridge described by Subsection (a)(2) provides the only public vehicular access from an origin or to a destination by a holder of a permit issued under § 623.011.