“Recreational vehicle” means both of the following:
(a) A motor home, travel trailer, truck camper, or camping trailer, with or without motive power, designed for human habitation for recreational, emergency, or other occupancy, that meets all of the following criteria:
(1) It contains less than 320 square feet of internal living room area, excluding built-in equipment, including, but not limited to, wardrobe, closets, cabinets, kitchen units or fixtures, and bath or toilet rooms.
(2) It contains 400 square feet or less of gross area measured at maximum horizontal projections.
(3) It is built on a single chassis.
(4) It is either self-propelled, truck-mounted, or permanently towable on the highways without a permit.
(b) A park trailer, as defined in Section 18009.3.