Every vehicle carrying trash upon a highway shall be covered with a cover sufficient to prevent any material from failing or being blown from such vehicle; provided, however, when traveling from house to house or from place to place to pick up material, vehicles used in collecting trash or garbage need not be covered so long as the distance between such stops for loading is not more than one-half (1/2) mile.
(§§ 7154 and 7154.1, T.O.O.C.)