The driver of a vehicle shall not drive within any sidewalk area except at a permanent or temporary driveway. A driver of a vehicle shall not drive on or across any constructed curb which is affixed to a public street. Where curbs are in place, a vehicle may only enter or leave realty abutting thereon by way of a driveway. The only exception to the foregoing shall be in those cases in which the owner or tenant of any such abutting realty first requests and receives permission from the Mayor to cross said curb or sidewalk. The Mayor is authorized to grant such permission on a case by case basis; however, in no such case shall permission be granted for purposes of extended daily parking.