Elevator-style car parks were still quite a novelty when this cutaway was published in 1920.
The garage shown could hold 6x the number of cars that a comparable, ordinary garage could hold.
This garage was basically all elevators: 42 elevators that retained the cars during the stay rather than off-loading them. Each elevat0r could hold 7 cars, for a total of 294 cars per garage.
Source: Popular Science Monthly February 1920