Mechanized and automatic parking systems cannot be precisely distinguished from each other. With the so-called semi-automated group of parking systems a part of the parking process is done with mechanical help in a process sequence consisting of at least two conveyor operations. A separate transfer cabin does not exist. The driver pulls the vehicle directly onto the parking palette, the subsequent lifting and shifting processes take place automatically.
Examples of semi-automated systems include:

Parking lifts with shifting palettes
Parking lifts with shifting palettes use palettes with horizontal doorways; palettes are laterally moveable. Palettes above and below are vertically retrievable to the doorway, thus the doorway must include an empty space. Parking is done through the vertical grid of the parking levels.

Automated parking systems are parking systems with conveyor facilities; a vehicle is parked into a transfer cabin by using its own engine power and is then shifted with a conveyor unit into a storage cabin (parking space, parking shelve). The following parking process takes place automatically.

Storage is carried out either statically or dynamically. If the storage process is static, the parked vehicle remains on its place for the whole time of parking. If it is dynamic, the vehicle could be shifted when other cars need to be parked.

The following main groups of automated parking systems exist:

Parking shelves
Parking shelves are automated parking systems which mainly follow static storage principles, where parked cars are shifted into a parking shelf by means of conveyor facilities. The control of the lifting and shifting process happens automatically. The transport of the vehicles is done via different aisles and stacks which are situated next to the parking spaces.
Parking shelves exist mostly in the design of high-rise stacks with operating unit (storage and retrieval unit), parking systems with shuttle-lift technology or tower systems with rectangular or circular layout and central, vertical conveyor. Usually, one to three vehicles are parked in line. Depending on the layout of the system, parking spaces are arranged either parallel, at right angles, radial or tangential to the aisles or elevator shaft. 
 

Parking shelves can be designed with or without palettes. In systems using palettes, the vehicle is parked directly on the palette. To enhance the logistics of parking and retrieval of empty palettes, different solutions are available according do size and concept of the system (palette changer/ storage). Alternatively, there are systems without palettes, which eliminate the handling of empty palettes. As technical solutions the comb system, various roller-grasping systems and conveyor-belt systems are common, for example.

Cycle moving parking system (palette shifting system)
Cycle moving parking systems utilize a dynamic storage principle, where palettes need to be shifted partially or completely within the system to retrieve an empty pallet or a vehicle that is to be pulled out to the transfer cabin. In this case, several palettes need to be shifted most of the time. Parking palettes are either shifted separately or on block within the parking deck or separately between connected levels or aisles.

Continous circulating parking systems (Mary-go-round)
Meanwhile, continous circulating parking systems (horizontal elevators) have been replaced by shifting systems for new facilities built in Germany. Vehicle parking systems in the design of vertical elevators have been rather uncommon in Germany, the reason being the fact that high loads must be shifted which requires complex mechanical constructions.