No vehicle shall be driven or moved on any public street unless such vehicle is so constructed or loaded as to prevent any of its load from dropping, shifting, leaking or otherwise escaping therefrom, except that sand or gravel and like substances, may be dropped for the purpose of securing traction, or water or other substance may be sprinkled on a road surface for the cleaning or maintaining of same by public authority or by persons under contract or other authorization by such public authority.
(1992 Code, § 96.11)