This book focuses on the design of the in-car human machine interface (HMI) and the design-relevant psychology

This study investigates the effect of peripheral visual and haptic information in providing information about upcoming motions of a fully automated vehicle to an occupant engaging in a non-driving related task, i.e. reading. Two peripheral displays, one visual and the other haptic, were designed and tested. It was hypothesized that the peripheral information would enhance the users' situation awareness and reduce their mental workload. The study was conducted with 18 participants driven around in a real-road environment in a multi-purpose vehicle that simulated a fully automated vehicle. The peripheral visual and haptic information significantly enhanced situation awareness but did not reduce the mental workload. Implications and future work are discussed.

While the fully automated vehicle (AV) has been the future of the automotive industry, there is uncertainty regarding how the vehicle will be operating. This study aims to investigate the feeling of comfort in terms of experienced motion sickness for the AV passengers when exposed to two different automated test rides. Two sessions were performed on the real road using an instrumented vehicle. The first session was a defensive automated test ride (DATR) with relatively low acceleration forces. The second session was an assertive automated test ride (AATR) with stronger acceleration forces. Electrocardiogram (ECG) and self-rating questionnaires were used to investigate the relation between them when given forces variation. Statistically significant (p<0.05) increases were found when comparing the before and after self-rating motion sickness score for the AATR, whereas no statistically significant (p<0.05) increases were found for the DATR. For the discomfort rating, the level of perceived comfort remained almost constant throughout DATR. Whereas for the AATR, an approximately linear increase in the feeling of discomfort was found. The physiological variations (ECG) could not accurately predict the subjective comfort based on the statistical analysis results. The linear regressions suggest that forces resulted from driving should be kept as low as possible to improve the AV riding experience.

In this chapter, we analyse the different levels of control involved in driving. Furthermore, we discuss the concept of situation awareness. Maintaining good situation awareness is central to safe driving. Finally, while situation awareness is central to the driving task, drivers may engage in other activities (“multi-task”), in particular when mental load is moderate. However, such additional activities may cause distraction and therewith impede situation awareness.

In this chapter, we discuss the human factors of driving automation. First, we go into the objectives of driving automation, and conclude that, from a safety perspective, attempts to automate driving certainly make sense. However, full automation will not appear in the market overnight, and consumers will be exposed to intermediate levels of automation. We discuss issues with different levels of automation, and what they mean for design. Furthermore, we discuss human factors issues that apply to all levels of automation: how to make sure that people understand and trust the automated system; what needs for shared control may be expected; what may be expected with regards to acquisition and loss of driving skill; what ethical issues may arise and how should these be dealt with; and, finally, do interests of individual customers and society in automated driving converge; if not, how can design contribute towards a solution. Finally, we go into design consequences and opportunities of the fact that automated vehicles will interact with other road users.

This on-road study explores the effect of a visual (VPIS) and haptic peripheral information system (HPIS) on a user’s level of motion sickness when engaging in reading activity while being driven in a fully automated vehicle (AV). Both systems notify the user regarding the upcoming navigational information in the lateral direction, and HPIS also supports the user from being involuntarily moved by the lateral acceleration when cornering. It was hypothesized that both systems would reduce the experienced motion sickness compared to those without any intervention. Eighteen participants with severe motion sickness susceptibility were exposed to lowfrequency lateral acceleration that induces a moderate-to-severe dose of motion sickness. The automated driving was simulated by an automated-like instrumented vehicle and performed with the Wizard-of-Oz approach. The participants were asked to perform reading while being exposed to three different conditions (control-, VPIS-, and HPIS-condition), each for about 15-minutes. Results from a self-rating questionnaire indicated statistically significant decreases in motion sickness found with the presence of HPIS but not with VPIS. Results showed HPIS produced the least experienced motion sickness while VPIS exacerbated the symptoms of motion sickness. Adaptation effects were also found due to the repetitive exposure to the same route of automated driving.

External Human-Machine Interfaces (eHMIs) are expected to bridge the communication gap between an automated vehicle (AV) and pedestrians to replace the missing driver-pedestrian interaction. However, the relative impact of movement-based implicit communication and explicit communication with the aid of eHMIs on pedestrians has not been studied and empirically evaluated. In this study, we pit messages from an eHMI against different driving behaviors of an AV that yields to a pedestrian to understand whether pedestrians tend to pay more attention to the motion dynamics of the car or the eHMI in making road-crossing decisions. Our contributions are twofold: we investigate (1) whether the presence of eHMIs has any objective effect on pedestrians' understanding of the vehicle's intent, and (2) how the movement dynamics of the vehicle affect the perception of the vehicle intent and interact with the impact of an eHMI. Results show that (1) eHMIs help in convincing pedestrians of the vehicle's yielding intention, particularly when the speed of the vehicle is slow enough to not be an obvious threat, but still fast enough to raise a doubt about a vehicle's stopping intention, and (2) pedestrians do not blindly trust the eHMI: when the eHMI message and the vehicle's movement pattern contradict, pedestrians fall back to movement-based cues. Our results imply that when explicit communication (eHMI) and implicit communication (motion-dynamics and kinematics) are in alignment and work in tandem, communication of the AV's yielding intention can be facilitated most effectively. This insight can be useful in designing the optimal interaction between AVs and pedestrians from a user-centered design perspective when driver-centric communication is not available.

Riding in an autonomous vehicle while doing non-driving related tasks can induce uncomfortable feelings related to motion sickness. Patting on oneself is considered a way to produce a calming effect by developing a comfortable feel. This paper explored two vibration patterns to imitate patting on the forearm. Twenty participants took part in this proof of concept study. They were exposed to both vibration patterns on their forearm in a static condition. A questionnaire assessed the responses. The results show that both patterns can produce a calming effect on the user.

Motion sickness (MS) mitigation devices have gained attention in the research related to automated vehicle (AV) driving. While different modalities have been proposed, the visual-related modality has shown promises as most activities inside the AV. In this study, we measured the level of MS experienced by the 38 participants using two visual-based prototypes when they underwent the automated driving test rides. Results indicated that participants experienced less MS when using P1 than P2.

There is a growing body of research in the field of interaction between automated vehicles and other road users in their vicinity. To facilitate such interactions, researchers and designers have explored designs, and this line of work has yielded several concepts of external Human-Machine Interfaces (eHMI) for vehicles. Literature and media review reveals that the description of interfaces is often lacking in fidelity or details of their functionalities in specific situations, which makes it challenging to understand the originating concepts. There is also a lack of a universal understanding of the various dimensions of a communication interface, which has impeded a consistent and coherent addressal of the different aspects of the functionalities of such interface concepts. In this paper, we present a unified taxonomy that allows a systematic comparison of the eHMI across 18 dimensions, covering their physical characteristics and communication aspects from the perspective of human factors and human-machine interaction. We analyzed and coded 70 eHMI concepts according to this taxonomy to portray the state of the art and highlight the relative maturity of different contributions. The results point to a number of unexplored research areas that could inspire future work. Additionally, we believe that our proposed taxonomy can serve as a checklist for user interface designers and researchers when developing their interfaces.