Theoretically double-deck elevators more than double the handling capacity during up-peak periods compared to the same amount of single deck elevators in the same shafts. This happens if the double-deck elevators stop to every other floor and serve two adjacent floors simultaneously. A general approach is that from the main entrance floors, the lower deck serves odd floors and the upper deck serves even floors. Passengers are guided to use escalators to select the correct deck when traveling to even or odd floors. As soon as the elevator stops to a call from an upper floor, car calls to any destination floor are admitted. A well-known approach in serving landing calls is that the landing calls are allocated to the trailing deck. The leading deck serves the calls that are coincident with the stops of the trailing car. A more efficient solution is to choose the landing call to the best deck. Best deck can be chosen for instance to minimize passenger waiting and journey times.