It is very important for buyers to distinguish between retrieval time and throughput. Retrieval time is defined as, “The elapsed time from the point at which a patron requests their vehicle (assuming parking is already paid for) to the point at which the automated parking system can deposit the patron’s car into the transfer compartment.” Throughput is defined as, “The percentage or total number of cars out of the total garage capacity that can enter or exit in one hour.”
Many automated parking system suppliers tout fast retrieval times, and they are able to demonstrate them quite reliably. However, it is critical to note they are only referring to the time required for a single transaction. The time required for a single transaction is of little value during the peak hours of operation when there is a steady flow of simultaneous storage and retrieval requests.
To understand the irrelevance of promoting the time for a single transaction, one need only consider that inside each automated parking system there are many mechanisms each of which must interact with each other for each transaction. In all systems, there will be times when one mechanism must wait for another mechanism to complete a task, and thus the retrieval time and the throughput must logically be negatively impacted.
The more simultaneous transactions an automated parking system must perform, the more likely it is that retrieval times will increase and throughput will decrease. This is especially true with all mono-path rack & rail systems where there is only one lane of lateral movement and the mechanisms cannot pass by each other on the rail. It is easy to envision the ensuing delays which occur when multiple cars are requested to be retrieved at the same time, from the same end, of the same floor within a mono-path system. Since patrons departure from the system is often random and unpredictable, there is really no way to avoid the slow retrieval times and lessened throughput in mono-path systems during periods of peak demand.
Boomerang’s RoboticValet automated parking system minimizes the negative impact on retrieval times and throughput during peak demand spikes by sending multiple robots to any area of any floor of the garage via multiple pathways (even moving underneath parked cars). The RoboticValet system then simultaneously acquires and removes the cars blocking the target vehicle, either by shifting them sideways or temporarily staging them on the concrete floor in the center transit aisle - all of which is impossible in any other system.