Access to cemeteries and mausoleums shall be limited to arterial streets, or collector streets with the express permission of the City Engineer. Access drives shall be designed to minimize traffic congestion, and in particular shall provide off-street parking that will reasonably accommodate average and ordinary funeral processions without obstructing any public street. A buffer yard with a minimum width of 20 feet and including a wall having a minimum height of six or a coniferous hedge having a minimum width of three feet and height of six feet shall be provided and permanently maintained along all property lines that adjoin properties that are zoned or planned for residential use.