By double parker these half car lifts are meant. The first car drives on it. The car lift goes up (the car is at least lifted from the rear and then another car can be parked in the same spot. In the better and more expensive ones, space underneath is also excavated so that the first car can leave again without the second car having to leave first. In the cheaper ones, it is like parking one behind the other, just with a smaller footprint. The development plan is probably intended to prevent morning maneuvering.