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.
Official text of the Texas Transportation Code as published by the Texas Legislative Council.