An off-street parking space shall be defined for the purpose of this Zoning Ordinance as an area that is no less than 9 feet wide and 18 feet deep and at least 162 square feet in size, exclusive of driveways, permanently reserved and available for the storage of one automobile which is enclosed in a building or unenclosed, is not in a public right of way and which has satisfactory ingress and egress to a public street or alley.