What do you mean 'allowed?', it's virtually mandated.
Most zoning laws force people to park real estate, walk around anywhere in SF, and look up, the lack of an additional 55 floors are 'parked' condos that aren't even allowed to exist, let alone sit empty.
Most zoning laws force people to park real estate, walk around anywhere in SF, and look up, the lack of an additional 55 floors are 'parked' condos that aren't even allowed to exist, let alone sit empty.