In City-owned parking lots, the Council may limit the sizes and types of motor vehicles to be parked thereon, hours of parking, and prescribed method of parking; provided, that such limitations and restrictions are marked or sign-posted thereon. It is unlawful to park or leave standing any vehicle backed into a parking place, to drive in a direction opposite the flow of traffic marked by "one-way" signs or arrows, or to park any vehicle in any City-owned parking lot contrary to the restrictions or limitations marked or sign-posted therein. (1988 Code § 9.12)