23330. Except where a special permit has been obtained from the
Department of Transportation under the provisions of Article 6
(commencing with Section 35780) of Chapter 5 of Division 15, none of
the following shall be permitted on any vehicular crossing:
  (a) Animals while being led or driven, even though tethered or
harnessed.
  (b) Bicycles or motorized bicycles, unless the department by signs
indicates that either bicycles or motorized bicycles, or both, are
permitted upon all or any portion of the vehicular crossing.
  (c) Vehicles haveing a total width of vehicle or load exceeding 102
inches.
  (d) Vehicles carrying items prohibited by regulations promulgated by
the Department of Transportation.