For the purpose of this chapter, the following terms shall have the meanings indicated:
Any vehicle used or intended to be used as a conveyance upon public streets or highways and duly licensed as such; and shall include self-propelled vehicles which are so designed and constructed or reconstructed or added to by means of accessories in such manner as to permit the occupancy thereof as a temporary dwelling or sleeping place for one or more persons, and having no foundation other than wheels, jacks or other mechanism so arranged as to be integral with or portable by trailer or camp car.