Extending head-up displays

Drivers consume an increasing amount of information while driving. The information is accessed on the in-car displays but also on personal devices such as the smartphone. Head-up displays are designed for a safe uptake of additional visual information while driving but their benefits are limited by the small display space. This motivates academia and industry to advance the head-up to the so-called windshield display. A windshield display will provide an extended display space, which largely or entirely covers the driver’s visual field through the windshield, as well as 3D and depth perception. Technologically, they are not yet feasible, but, thanks to steady advancements they will become available in the future. Extending a small 2D to a large 3D space requires a rethinking of the entire user interface. The windshield display opens up new opportunities for the type and amount of information, as well as for the way it is presented – ranging up to full augmented reality but it also raises concerns about a distracted driver. The core question of this thesis is whether such an extension is reasonable and desirable – meaning if there are convincing arguments and use cases which justify the potential risk of distraction. This thesis presents our research about the risks and benefits of the transition from a head-up to a windshield display. Thus, we explore the potentials and examine the safety risks and benefits as well as the drivers’ satisfaction of various display aspects. We developed a design space that shows how the new size and depth possibilities create new, or interrelate with existing, design factors. New design opportunities arise and suggest a redesign of existing functionality but also the integration of new content. We researched the information content that could be displayed on a windshield display and asked drivers what content they need and personally desire. We thereby obtained an extensive list of use cases and applications. We approached the question of where such content should be displayed, given the large 3D space. To enable the design of safe interfaces, we first examined the driver’s visual perception across the windshield and identified locations that promote information recognition, particularly in the new peripheral area. Simultaneously, we examined the different ways of placing and stabilizing the content. We compared the traditional screen-fixed with world-fixed (augmented reality) and head-stabilized placement methods in terms of user satisfaction, understandability and safety. The gained knowledge about the locations that support information uptake and about the best ways of placing content was merged into a layout concept that subdivides the driver’s view into several information areas. We also incorporated the drivers’ preferences into this design process and compared their personalized layouts with our vision-based layout concept. We assessed the safety of both layout versions and present a revised concept. We close this thesis by reflecting on other trends that may interrelate with the windshield display, namely autonomous driving and augmented reality consumer devices. We look at recent advancements in realizing windshield displays and endeavor a prediction of future developments in this area.