339.11   SHIFTING CARGO; LOOSE LOADS.
   (a)   No person shall drive, or require or permit any motor vehicle or trailer to be driven, unless such motor vehicle or trailer is constructed or equipped with adequate header boards or similar devices of sufficient strength, load fastening devices and blocking, and unless the load or cargo thereon is properly distributed and securely fastened, braced and blocked, to prevent any portion of the load from penetrating or crushing the driver's compartment or cargo compartment wall, or from falling, spilling or rolling upon the roadway, when such vehicle or trailer is involved in an accident or when subjected to the maximum braking deceleration of which it is capable.
   (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.
   Penalty - see Sections 307.01 and 307.02