(a) This subchapter does not authorize the operation on the national system of interstate and defense highways in this state of a vehicle of a size or weight greater than those permitted under 23 U.S.C. Section 127.
(b) If the United States authorizes the operation on the national system of interstate and defense highways of a vehicle of a size or weight greater than those permitted under 23 U.S.C. Section 127 on September 1, 2013, the new limit automatically takes effect on the national system of interstate and defense highways in this state.