The Board of Standards and Appeals may permit accessory group parking facilities with more than 150 spaces for hospitals and related facilities listed under Use Group III(B) in all Residence Districts, provided that the following findings are made:

1. that such facility is so located as to draw a minimum of vehicular traffic to and through local streets in residential areas;
2. that such facility has adequate reservoir space at the vehicular entrance to accommodate either 10 automobiles or five percent of the total parking spaces provided by the facility, whichever amount is greater, but in no event shall such reservoir space be required for more than 20 automobiles; and
3. that the streets providing access to such use will be adequate to handle the traffic generated thereby.

The Board may prescribe appropriate conditions and safeguards to minimize adverse effects on the character of the surrounding area, including requirements for locations of entrances and exits or for shielding of floodlights.