| Problems associated with wayfinding in airport terminals are not new to airport terminal architects and planners. It is a common knowledge that some people have difficulties in locating their destinations in spite of availability of signs. Reasons for this are said to be multifarious, and they include the complexity of the terminal and the wayfinding aids within it.;This research builds on the quantitative models of evaluating human orientation in complex buildings. Braaksma and Cook (1980) proposed a measure called visibility index (VI), the value of which indicates the ease of orientation in a terminal. Tosic and Babic (1984) proposed some modification to the evaluation of VI, while O'Neill (1984) proposed a measure called inter-connection density (ICD) for measuring the complexity of a building layout.;Signs are commonly used to bring a target that is not visually perceptible to a virtual location, but there is a reduction in the available visual access to a target when signs are involved. The effects of number of signs, or decision points and number of level changes on visual access are investigated. A relationship between the slowness in reaching a target, the number of decision points, and the number of level changes is developed. The relationship is used as a reduction factor in the VI model.;Secondary activities are not of the same importance neither are they of equal importance with the primary activities. In order to call appropriate attention to these activities and to compare the VI of different terminals, the weights of the secondary activities need to be determined. A survey of 32 terminal activity centres was conducted. The ranks and the weights of these activity centres were determined based on survey responses from airport users at three airports. The weights are incorporated into the VI model.;The relationship between visibility index and inter-connection density is established. Based on the pre-occupancy survey of five airports, VI was found to be linearly related to ICD. The VI of generic terminals are evaluated. The centralized radial pier-finger terminal is found to have the highest value of VI, while the semi-centralized circular satellite has the least VI.;Levels of service A to E and A to C are defined. Values of VI, ICD, and the combination of the two measures that correspond to these levels of service are proposed. |
