When discussing the term design in the context of elevator systems, it is important to distinguish between two main areas of elevator design: engineering design and traffic design. Engineering design involves the electrical and mechanical design of the various components and systems in the elevator. Traffic design involves the design of the elevator system such that it can transport the required number of passengers in a specified period of time under the stipulated performance conditions. This series of articles is only concerned with the traffic design of elevator systems, rather than the engineering design. However, it is necessary in certain cases to deal with certain engineering design topics due to the fact that they are closely linked with traffic design aspects and have a significant impact on decisions made within the traffic design process. An example is the effect of shaft space on the selection of the rated speed of the elevator, where the selection of the rated speed of the elevator requires minimum clearances in the pit and the head of the shaft, referred to as pit depth and headroom respectively. The aim of elevator traffic engineering is to achieve a compromise between cost and performance. A number of parameters have to be optimized such as the average passenger waiting time, the average passenger travelling time and the energy consumed by the elevators. The used core space must also be minimized in the building, in order not to take up valuable net usable area. The solution of the vertical transportation problem identifies the number of the elevators to be used (as well as well as their rated speed and rated capacity) in the building in order to achieve the required performance. In effect, the vertical transportation problem is a multiple-constraint-multiple-objective problem that aims to produce a solution that meets the following requirements: (1)Functional. (2)Safe. (3) Reliable. (4)Cost effective. (5)Meets the passenger performance requirements (waiting time and travelling time). (6)Uses the smallest possible core space of the building. (7)Energy efficient. In order to solve the problem, it is necessary to identify demand and supply. Demand is represented by the arrival of passengers for service. Supply is represented by the number of elevators, their rated speed and rated capacity.