Volume 18, Issue 2 - Special Issue "User-Centered Design for Automated Vehicles: HMIs, User Needs, and Preferences"

This paper investigated the influence of VR-entertainment systems on passenger and entertainment experience in vehicles with smooth movements. To simulate an autonomous driving scenario, a tablet and a mobile VR-HMD were evaluated in a dynamic driving simulator. Passenger, user and entertainment experience were measured through questionnaires based on comfort/discomfort, application perception, presence, and simulator sickness. In two experiments, two film sequences with varying formats (2D versus 3D) were presented. In Experiment 1, the established entertainment system (tablet + 2D) was tested against a possible future one (HMD + 3D). The results indicated a significantly more favorable experience for the VR-HMD application in the dimensions of user experience (UX) and presence, as well as low simulator sickness values. In Experiment 2, the film format was held constant (2D), and only the device (tablet versus HMD) was varied. There was a significant difference in all constructs, which points to a positive reception of the HMD. Additional analyses of the HMD device data for both experiments showed that the device and not the film format contributed to the favorable experience with the HMD. Additionally, the framework to evaluate the new application context of VR as an entertainment system in autonomous vehicles was discussed.

Increasing vehicle automation presents challenges as drivers of highly automated vehicles become more disengaged from the primary driving task. However, even with fully automated driving, there will still be activities that require interfaces for vehicle-passenger interactions. Windshield displays are a technology with a promising potential for automated driving, as they are able to provide large content areas supporting drivers in non-driving related activities. However, it is still unknown how potential drivers or passengers would use these displays. This work addresses user preferences for windshield displays in automated driving. Participants of a user study (N=63N=63) were presented two levels of automation (conditional and full), and could freely choose preferred positions, content types, as well as size, transparency levels and importance levels of content windows using a simulated “ideal” windshield display. We visualized the results in form of heatmap data which show that user preferences differ with respect to the level of automation, age, gender, or environment aspects. These insights can help designers of interiors and in-vehicle applications to provide a rich user experience in highly automated vehicles.

Autonomous buses are expected to become a cornerstone of future mobility systems. Especially during their introduction, passengers may require reassurance about the vehicle’s awareness of the situation on the road and of its intended next actions to further acceptance. In order to investigate the need and requirements for information about the vehicle’s awareness and intent from the perspective of first-time users, we conducted two user studies in a state-of-the-art autonomous bus at public demonstration spaces. In the first study, participants underwent a demonstration ride with the bus and were then asked about their needs for awareness and intent communication. The second study took participants on a ‘simulated ride’ within a stationary bus, in which typical scenarios of the road ahead were presented, together with different awareness and intent cues. Our results suggest that, first, future autonomous bus passengers may be in need of such awareness and intent communication screens. Second, we found that awareness and intent communication may be of greater importance for the indication of potential hazard recognition than for indicating route directions. Third, due to their complementary strengths, none of the three compared types of visual communication (text, icon and augmented reality) should be used in isolation.

Highly automated cars will be on the worlds’ roads within the next decade. In highly automated driving the vehicle’s lateral and longitudinal controls can be passed on from the driver to the vehicle and back again. The design of a vehicle’s take-over requests will largely determine the driver’s performance after taking back vehicle control. In the scope of this paper, potential drivers of highly automated cars were asked about their preferences regarding the human-machine interface design of take-over requests. Participants were asked to evaluate eight different take-over requests that differed with respect to (a) take-over request procedure (one-step or two-step procedure), (b) visual take-over request modality (text or text and pictogram), and (c) auditory take-over request modality (tone or speech). Results showed that participants preferred a two-step procedure using text and speech to communicate take-over requests. A subsequent conjoint analysis revealed that take-over requests ideally use speech output in a two-step procedure. Finally, a detailed evaluation showed that the best take-over request interface received significantly higher user experience ratings regarding product characteristics as well as users’ emotions and consequences of product use than the worst take-over request interface. Results are related to the background literature and practical implications are discussed.