In a conventional call system, the users push up and down buttons, and elevators answer the call. This system works fine in buildings that have low “vertical ridership” and do not experience “rush hour” traffic. In heavy traffic, lots of buttons are pushed that will result in lots of elevator stops, increasing travel and wait time. In a high speed elevator, say with a speed of 6 m per second, each stop may require as much as 10–13 s. To address this problem, elevator designers have invented the Destination Dispatching System (DDS).
It was first introduced in the 1990s following the surge of increased microprocessor capacity during the 1980s. A DDS is an optimization technique used for multi-elevator installations, which groups passengers for the same destinations into the same elevators. In real-time, the system analyzes input data from passengers and efficiently groups their destinations, resulting in decreasing the number of stops in every elevator’s trip.
Upon entering a destination by using keypads or touch screens on the Destination Operation Panel (DOP), usually placed strategically in the lobby, the system quickly signals and directs each passenger to the assigned elevator to board the DDS provides important benefits including decreasing energy consumption, reducing waiting time, and minimizing crowding and congestion in the building lobbies and hallways. DDS’ manufacturers claim that the average traveling time can be reduced by about 30 percent. Katherine Rosman indicates that the average wait time for the elevator in a typical 16-floor building with a dispatch system is 13 s, while the average wait time for the elevator in the same building with a conventional system is 138 s.
In addition to saving time, the system eases pedestrian traffic flow since each passenger heads directly to a specific elevator, eliminating the need to rush to every arriving elevator, a common behavior exhibited by passengers. The system also improves accessibility, as a mobility-impaired passenger can move to his or her designated car in advance. The DDS is mostly appreciated during elevators’ “rush hours”, usually experienced in the morning and lunchtime . Due to increased efficiencies in handling a large number of people, DDS reduces the required number of elevators. It also decreases wear-and-tear factor because elevators make fewer stops.
