Nora Broy

A data set of real world driving to assess driver workload

Driving a car is becoming increasingly complex. Many new features (e.g., for communication or entertainment) that can be used in addition to the primary task of driving a car increase the drivers workload. Assessing the drivers workload, however, is still a challenging task. A variety of means are explored which rather focus on experimental conditions than on real world scenarios (e.g., questionnaires). We focus on physiological data that may be assessed in an non-obtrusive way in the future and is therefore applicable in the real world.n Hence, we conducted a real world driving experiment with 10 participants measuring a variety of physiological data as well as a post-hoc video rating session. We use this data to analyze the differences in the workload in terms of road type as well as especially important parts of the route such as exits and on-ramps. Furthermore, we investigate the correlation between the objective assessed and subjective measured data.

Investigating user needs for non-driving-related activities during automated driving

In this paper, we investigate which non-driving-related activities drivers want to perform while driving highly or fully automated. Beyond the available advanced driving assistance functions, we expect that highly automated driving will soon be available in production vehicles. While many technological aspects have been investigated, it is not yet clear (a) which activities the drivers want to perform once they do not have to steer or monitor their car any more and (b) which of those will be feasible. In contrast to prior (survey-based) research, we investigate the drivers needs for such activities by employing a combination of a web survey, in-situ observations, and an in-situ survey. Also, we have a look at the specific requirements of the European / German market in contrast to prior research conducted mostly for English-speaking countries. The findings indicate that besides traditional activities (talking to passengers, listening to music), daydreaming, writing text messages, eating and drinking, browsing the Internet, and calling are most wanted for highly automated driving. This shows the potential for mobile and ubiquitous multimedia applications in the car.

FrameBox and MirrorBox: tools and guidelines to support designers in prototyping interfaces for 3D displays

In this paper, we identify design guidelines for stereoscopic 3D (S3D) user interfaces (UIs) and present the MirrorBox and the FrameBox, two UI prototyping tools for S3D displays. As auto-stereoscopy becomes available for the mass market we believe the design of S3D UIs for devices, for example, mobile phones, public displays, or car dashboards, will rapidly gain importance. A benefit of such UIs is that they can group and structure information in a way that makes them easily perceivable for the user. For example, important information can be shown in front of less important information. This paper identifies core requirements for designing S3D UIs and derives concrete guidelines. The requirements also serve as a basis for two depth layout tools we built with the aim to overcome limitations of traditional prototyping when sketching S3D UIs. We evaluated the tools with usability experts and compared them to traditional paper prototyping.

Is stereoscopic 3D a better choice for information representation in the car

In modern cars users need to interact with safety and comfort functions, driver assistance systems, and infotainment devices. Basic requirements include the perception of the current status and of information items as well as the control of functions. Handling that myriad amount of information while driving requires an appropriate interaction design, structure and visualization of the data. This paper investigates potentials and limitations of stereoscopic 3D for visualizing an in-vehicle information system. We developed a spatial in-car visualization concept that exploits three dimensions for the systems output. Based on a prototype, that implements the central functionality of our concept, we evaluate the 3D representation. A laboratory study with 32 users indicates that stereoscopic 3D is the better choice as it improves the user experience, increases the attractiveness, and helps the user in recognizing the current state of the system. The study shows no significant differences between non-stereoscopic and stereoscopic representations in the users workload. This indicates that stereoscopic visualizations have no negative impact on the primary driving task.

Perceiving layered information on 3D displays using binocular disparity

3D displays are hitting the mass market. They are integrated in consumer TVs, notebooks, and mobile phones and are mainly used for virtual reality as well as video content. We see large potential in using depth also for structuring information. Our specific use case is 3D displays integrated in cars. The capabilities of such displays could be used to present relevant information to the driver in a fast and easy-to-understand way, e.g., by functionality-based clustering. However, excessive parallaxes can cause discomfort and in turn negatively influence the primary driving task. This requires a reasonable choice of parallax boundaries. The contribution of this paper is twofold. First, we identify the comfort zone when perceiving 3D content. Second, we determine a minimum depth distance between objects that still enables users to quickly and accurately separate the two depth planes. The results yield that in terms of task completion time the optimum distance from screen level is up to 35.9 arc-min angular disparity behind the screen plane. A distance of at least 2.7 arc-min difference in angular disparity between the objects significantly decreases time for layer separation. Based on the results we derive design implications.

Using eye-tracking to support interaction with layered 3D interfaces on stereoscopic displays

In this paper, we investigate the concept of gaze-based interaction with 3D user interfaces. We currently see stereo vision displays becoming ubiquitous, particularly as auto-stereoscopy enables the perception of 3D content without the use of glasses. As a result, application areas for 3D beyond entertainment in cinema or at home emerge, including work settings, mobile phones, public displays, and cars. At the same time, eye tracking is hitting the consumer market with low-cost devices. We envision eye trackers in the future to be integrated with consumer devices (laptops, mobile phones, displays), hence allowing the users gaze to be analyzed and used as input for interactive applications. A particular challenge when applying this concept to 3D displays is that current eye trackers provide the gaze point in 2D only (x and y coordinates). In this paper, we compare the performance of two methods that use the eyes physiology for calculating the gaze point in 3D space, hence enabling gaze-based interaction with stereoscopic content. Furthermore, we provide a comparison of gaze interaction in 2D and 3D with regard to user experience and performance. Our results show that with current technology, eye tracking on stereoscopic displays is possible with similar performance as on standard 2D screens.

Introducing novel technologies in the car: conducting a real-world study to test 3D dashboards

Today, the vast majority of research on novel automotive user interface technologies is conducted in the lab, often using driving simulation. While such studies are important in early stages of the design process, we argue that ultimately studies need to be conducted in the real-world in order to investigate all aspects crucial for adoption of novel user interface technologies in commercial vehicles. In this paper, we present a case study that investigates introducing autostereoscopic 3D dashboards into cars. We report on studying this novel technology in the real world, validating and extending findings of prior simulator studies. Furthermore, we provide guidelines for practitioners and researchers to design and conduct real-world studies that minimize the risk for participants while at the same time yielding ecologically valid findings.

Design and evaluation of a layered handheld 3d display with touch-sensitive front and back

Touch screens became truly pervasive through the success of smartphones and tablet PCs. Several approaches to further improve the interaction with touch screens have been proposed. In this paper we combine and extend two of these trends. We present a mobile 3D screen that consists of a stack of displays and is touch sensitive on both display sides. This design makes the screen independent from the users view angle. Using a touch-sensitive back enables back-of-device interaction to avoid the fat-finger problem. Combining back-of-device interaction with a transparent display also avoids occlusion of the users finger on the back through the device. Through a study we investigate how back and front touch improves interaction with 3D content and show how back-of-device interaction is improved if the user can actually see the finger on the back.

Evaluating Stereoscopic 3D for Automotive User Interfaces in a Real-World Driving Study

This paper reports on the use of in-car 3D displays in a real-world driving scenario. Today, stereoscopic displays are becoming ubiquitous in many domains such as mobile phones or TVs. Instead of using 3D for entertainment, we explore the 3D effect as a mean to spatially structure user interface (UI) elements. To evaluate potentials and drawbacks of in-car 3D displays we mounted an autostereoscopic display as instrument cluster in a vehicle and conducted a real-world driving study with 15 experts in automotive UI design. The results show that the 3D effect increases the perceived quality of the UI and enhances the presentation of spatial information (e.g., navigation cues) compared to 2D. However, the effect should be used well-considered to avoid spatial clutter which can increase the systems complexity.

3D Displays in Cars: Exploring the User Performance for a Stereoscopic Instrument Cluster

In this paper, we investigate user performance for stereoscopic automotive user interfaces (UI). Our work is motivated by the fact that stereoscopic displays are about to find their way into cars. Such a safety-critical application area creates an inherent need to understand how the use of stereoscopic 3D visualizations impacts user performance. We conducted a comprehensive study with 56 participants to investigate the impact of a 3D instrument cluster (IC) on primary and secondary task performance. We investigated different visualizations (2D and 3D) and complexities (low vs. high amount of details) of the IC as well as two 3D display technologies (shutter vs. autostereoscopy). As secondary tasks the participants judged spatial relations between UI elements (expected events) and reacted on pop-up instructions (unexpected events) in the IC. The results show that stereoscopy increases accuracy for expected events, decreases task completion times for unexpected tasks, and increases the attractiveness of the interface. Furthermore, we found a significant influence of the used technology, indicating that secondary task performance improves for shutter displays.