A vehicle used exclusively to transport milk may be operated on a public highway of this state only if:(1) the distance between the front wheel of the forward tandem axle and the rear wheel of the rear tandem axle, measured longitudinally, is 28 feet or more; and(2) the weight carried on any group of axles is not heavier than 68,000 pounds. Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995. Amended by Acts 2001, 77th Leg., ch. 941, Sec. 33, eff. Sept. 1, 2001. Sec. 622.032. INTERSTATE AND DEFENSE HIGHWAYS. (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 that authorized by 23 U.S.C. Section 127, as amended.(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 that authorized by 23 U.S.C. Section 127 on August 29, 1977, the new limit takes effect on the national system of interstate and defense highways in this state. Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995.