SmartMMI includes the development of a working prototype of a semi-transparent, interactive display for public transport vehicles. In this user study we were able to test several design prototypes in our mockup tram compartment and gained valuable insight on the usability of several aspects of our prototypes.
Additionally, towards the end of our project, a field test is planned. Two prototypical semi-transparent displays will be implemented in a tram of the local public transport provider. We are currently planning the usability evaluation of our system in the field and in order to do that, we conducted a study to test various evaluation methods in the mockup tram department. We wanted to determine the best suitable evaluation methods for subsequent studies in real public transport environments. Based on the results of this study, we developed our evaluation concept for the upcoming field test.
For this study, we used the mockup configuration that closely matches the configuration of a local tram. We arranged the seats as four, two facing the direction of travel and two opposite to the direction of travel, which will be the seat arrangement present in the vehicle that will be used in our field test. The semi-transparent displays will be installed next to such a seat configuration, in the same dimensions as our interactive displays are installed in the tram mockup. As can be seen in the right figure, information for all passengers is displayed in the upper area, on the small screen. This screen displays the line number, destination, upcoming stops, transfer options, the arrival time at the following stations, the current time and weather, including a forecast. The two lower screens that will be semi-transparent in the field test are multi-touch enabled and, due to the seat configuration, can be operated by several people.
A network map and a geographical map can be accessed through the menu item at the bottom of the display. The geographical map is automatically centered on the location of the tram the user is currently sitting in. The maps can be explored interactively and display points of interest, other stations and additional detail information. On the opposite side of the tram department a 55 inch screen simulated the opposite window of the vehicle as shown in the left figure. During the study, a video shot along the entire route of the simulated tram line is shown on this display. The sound of opening and closing doors as well as the information displaying the next stops is synchronized with the video for consistent information.
Prior to the study itself, study participants were asked to fill out an online survey determining their technological affinity and public transport usage.
Based on the survey results the participants were grouped into three typical public transport usage groups (commuters, occasional users and tourists), based on public transport personas. Three specific scenarios were designed for each group. While participants classified as commuter were asked to complete tasks being situated in a simulated delay scenario, participants classified as tourists were faced with tasks associated with more touristic destinations and time irrelevant tasks.
A combination of pressed keys were used as a trigger for specific information displays on each display. This triggering approach allowed us to display different messages independent from each other and independent from time. The participants in different age groups between under 18 years and over 60 years, needed a little more time to familiarize themselves with the scenario and the interactive window, which is why the timing of additional information display was not synchronized for all participants. Even though this might lead to some discrepancies between the content of the notification and the timing of the video running in the background, the potential synchronicity error was classified as negligible. This approach of triggering events during a study by hand seems also more applicable for field studies, since the number of variables affecting time only increases when swapping the simulated environment for an actual moving vehicle.
The first step of the interaction with the interactive window, meaning the mere detection of a possible interaction came up as a potential usability issue throughout the study. Though the participants knew roughly what the study was about, some claimed that some sort of call to attention might be helpful to communicate the possibility to interact with the window. Due to the nature of the simulated tram and the overall concept of the studies, which have to be explained at least to a certain degree to the participants beforehand, it is difficult to measure the recognition of operability and the motivation to try it out. This should be easier to investigate further through field studies that will observe casual tram passengers, who sit beside the interactive window and may or may not use it unbeknownst to any study taking place, which is why we are also planning general observations in our field test.
The results of this study informed our field test concept, but also showed the limitations and possibilities of our tram mockup. We are planning more usability studies on public transport systems in our mockup and are also planning to further develop possible applications of the mockup.