In this paper we chart a design space for conversational in-vehicle information systems (IVIS). Our work is motivated by the proliferation of speech interfaces in our everyday life, which have already found their way into consumer electronics and will most likely become pervasive in future cars.

The objective of this tutorial is to provide MobileHCI newcomers to the domain of automotive user interfaces (AutomotiveUI) with an introduction and overview of the field. The tutorial will introduce the specifics and challenges of in-vehicle user interfaces that set this field apart from others. With a clear focus on the integration of mobile devices into the car, we will provide an overview of the specific requirements of AutomotiveUI, discuss the design of such interfaces, also with regard to standards and guidelines. We further outline how to evaluate interfaces in the car, discuss the challenges with upcoming automated driving and present trends and challenges in this domain.

Our eyes use multiple cues to perceive depth. Current 3D displays do not support all depth cues humans can perceive. While they support binocular disparity and convergence, no commercially available 3D display supports focus cues. To use them requires accommodation, i.e. stretching the eye lens when focusing on an individual distance. Previous work proposed multilayer and light field displays that require the eye to accommodate. Such displays enable the user to focus on different depths and blur out content that is out of focus. Thereby, they might ease the separation of content displayed on different depth layers. In this paper we investigate the effect of focus cues by comparing 3D shutter glasses with a multilayer display. We show that recognizing content displayed on a multilayer display takes less time and results in fewer errors compared to shutter glasses. We further show that separating overlapping content on multilayer displays again takes less time, results in fewer errors, and is less demanding. Hence, we argue that multilayer displays are superior to standard 3D displays if layered 3D content is displayed, and they have the potential to extend the design space of standard GUI.

In this paper, we present the S3D-UI Designer --- a tool to create prototypes for 3D displays. Stereoscopic (S3D) displays are quickly becoming popular beyond cinemas and home entertainments. S3D displays can today already be found in mobile phones, public displays, and car dashboards. A benefit of such UIs is that they can group and structure information in a way that makes them easily perceivable for the user. At the same time, prototyping these UIs is challenging, as with traditional techniques, UI elements cannot easily be rendered and positioned in 3D space. In contrast to professional 3D authoring tools, we present a tool targeted towards non-experts to quickly and easily sketch a S3D UI and instantly render it on a 3D display. We report on the design of the tool by means of a workshop and present an evaluation study with 26 participants assessing its usabilty.

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 driver's 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.

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.

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.

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.

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 user's 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 eye's 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.

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 driver's workload. Assessing the driver's 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.

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 system's 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.

Car rides are often perceived as dull by the passengers, especially children. Therefore, we aim to introduce a system fostering a collaborative and communicative experience in this environment. This paper presents the design for a game played together by all car-occupants, including the driver, according to their abilities and capacities. A fully implemented prototype of our system called nICE: nice In-Car Experience is evaluated under real world conditions in a user study with five families using a qualitative approach.

To create a common understanding of a software system, for users and developers, we believe that run-time visualization of both behavior and internal structure is critical. This is particularly true for distributed embedded systems, which are designed to be unobtrusive, making them difficult to comprehend for people who are not familiar with them. We suggest a novel method to visualize software behavior in real-time flexibly and comfortably, facilitating understanding of software. We conducted a feasibility study with a proof of-concept prototype. Our results indicate that visualizing structure and behavior in real-time supports software comprehension for new architects, developers and users, and can even provide new insights to experienced developers.