339.12  SPECIAL WEIGHT AND TIRE RESTRICTIONS.
   (a)   Whenever in the judgment of the Service-Safety Director any highway or part thereof would be injured or damaged by general use by vehicles having solid tires or by vehicles exceeding in gross weight or in weight per inch of tire width the limits which he shall determine to be safe for such highway or part thereof, he shall erect appropriate traffic signs prohibiting the operation of vehicles having solid tires, or indicating and designating such weight limits.  No person shall operate over any such highway or part thereof any vehicle having solid tires or exceeding such weight limits, without securing a permit as provided in Section 339.02.
(1979 Code 74.56)
   (b)   Whoever violates any provision of this section is guilty of a minor misdemeanor on a first offense; on a second offense within one year after the first offense, the person is guilty of a misdemeanor of the fourth degree; on each subsequent offense within one year after the first offense, the person is guilty of a misdemeanor of the third degree.