339.09 SHIFTING LOAD; LOOSE LOADS.
   (a)   In addition to any other lawful requirements of load distribution, no person shall operate any vehicle upon a street or highway unless such vehicle is so laden as to prevent its contents from shifting or otherwise unbalancing the vehicle to such an extent as to interfere with the safe operation of the same.
   (b)   No motor vehicle or trailer shall be driven unless the tailboard or tailgate, tarpaulins, chains (except ground or contact chains), ropes, stakes, poles, and the like, or any part of the load, are securely fastened to prevent dangling, flapping, swinging or falling from the side, end or top of the load or body.  All projecting cargo shall be properly guarded by a red flag or cloth or a red light or lantern as required by Section 337.08.
   (c)   Whoever violates 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.