It is unlawful for any vehicle to drive, operate or otherwise be moved over, along, across or to park or stand within the area north of a line between the northwest portion of the west wing of the County-City Building and the curb along the north boundary of east Nollmeyer Lane, except for assigned vehicles or vehicles authorized to use portions thereof by the Sheriff or Tacoma Police Department, and except that authorized vehicles engaged in loading or unloading supplies or equipment for the County-City Building may use the loading dock on the north side of the west wing of the County-City Building in such a manner as not to unreasonably disrupt traffic to the jail facility.