Abstract
Objective: This study aims to evaluate the efficiency of two representative subway map design types, namely a diagram type and a geographical type using physiological metrics, performance metrics, and self-reported metrics, which are representative usability metrics. Background: Subway maps need to be designed in order for users to quickly search and recognize subway line information. Although most cities' subway maps currently use the diagram type designed by Henry Beck, New York City's subway map has recently been changed to the subway map type combined with the geographical type designed by Michael Hertz. However, not many studies on its efficiency are found, and the studies that are available mainly depend on questionnaire surveys or take on a subjective behavioral study type based on experts' experiences. In this regard, evaluation through a more objective method is needed. Method: This study employed usability metrics as a method to evaluate the efficiency of information search targeting the diagram type and geographical type subway maps used mostly as subway maps. To this end, physiological metrics obtained through eye tracking, task completion time, representative metric of task performance, and subjective evaluation metrics were used for the suitability evaluation of subway map designs. Results: In the result of gaze movement distance analysis, no significant difference was shown in the two design types in terms of a process finding a departure station from the starting point and a process finding a transfer station between the departure station and arrival station (destination). However, the gaze movement distance in the process finding the arrival station at the departure station was significantly shorter in the geographical type, rather than in the diagram type. The analysis of task completion time showed a result similar to the gaze movement distance analysis result. Task completion time was significantly shorter in the geographical type, rather than in the diagram type, which is in the process finding the arrival station at the departure station. In other information search processes, no significant difference was shown. As a result of subjective evaluation metrics analysis, no significant difference was revealed in the two design types. Conclusion: An analysis on the two representative subway map design types was carried out via the adoption of usability metrics. As a result, although no significant difference was shown in some information search processes, it was revealed that information search was easier in the geographical type overall. Also, it was found that usability metrics can be effectively used to evaluate the design types of subway maps. Application: The study results can be used to set design direction to offer ease in information search on subway lines. The study also can be used as a method to evaluate a subway map's design type.