A very important impact of peak traffic (PT) handling of an automated parking facility is the dwell time (DT) of users—this is the actual time it takes the users to drive their cars into the entry / exit stations (EES) for the storage process. Dwell time is measured from the moment the entry / exit door opens, until the user has positioned his or her car and is out of the EES to initiate the storage process for the car by either swiping a card, pushing a button, or entering a PIN number on a touch screen.
Experience shows that the dwell time for storage is a critical component in achieving peak traffic performance. The DT at the retrieval portion of the parking procedure is negligible compared to the storage dwell time. The figure below illustrates the actual dwell time measurements during the first six months of operation in one of the Robotic Parking Systems. (These DT figures later decreased about 10% to 20%, thus creating a “cushion” for planning purposes of peak traffic.)
This figure shows the importance of the dwell time compared to the machine time (MT); both added together create the storage time (ST) per vehicle parking. Machine time is the time it takes to replenish the same entry / exit station for the next vehicle to enter after the previous user has initiated the storage process. Depending on the installed machinery components, the machine time ranges from 40 to 50 seconds. Thus, it is very clear that the impact of the dwell time to the overall peak traffic handling of an automated parking system can be significant. Therefore, measures installed in the entry / exit area to enable users to position their vehicles faster is a very important factor in the design of an automated parking facility. Such measures in the Robotic Parking System include special design of the pallet itself, sensors, clear positioning instructions displayed on screens in the entry / exit station and more.
For demonstration purposes, using an average dwell time of 40 seconds, and an average machine time of 50 seconds, translates into a 90 second storage cycle time per entry / exit station, which results in 40 vehicles / EES / hour. These and other calculations are used to determine the number of entry / exit stations and other machinery needed in the design of a Robotic Parking System for any project.