Stefan Brandenburg

Improving homogeneity by dynamic speed limit systems

Homogeneity of driving speeds is an important variable in determining road safety; more homogeneous driving speeds increase road safety. This study investigates the effect of introducing dynamic speed limit systems on homogeneity of driving speeds. A total of 46 subjects twice drove a route along 12 road sections in a driving simulator. The speed limit system (static-dynamic), the sophistication of the dynamic speed limit system (basic roadside, advanced roadside, and advanced in-car) and the situational condition (dangerous-non-dangerous) were varied. The homogeneity of driving speed, the rated credibility of the posted speed limit and the acceptance of the different dynamic speed limit systems were assessed. The results show that the homogeneity of individual speeds, defined as the variation in driving speed for an individual subject along a particular road section, was higher with the dynamic speed limit system than with the static speed limit system. The more sophisticated dynamic speed limit system tested within this study led to higher homogeneity than the less sophisticated systems. The acceptance of the dynamic speed limit systems used in this study was positive, they were perceived as quite useful and rather satisfactory.

Legibility of Letters in Reality, 2D and 3D Projection

Virtual prototypes are essential for engineers to understand the complex structures and arrangements of mechatronic products like automobiles. Currently, Virtual Environments (VE) are used for visual analysis and interaction with virtual models. In the next years more supplementary information will be integrated in the VE, completing the 3D-model. This includes names of single parts, corresponding materials or masses. However, up till now there is little explicit research on the psychological effects of additional text visualization in VE’s. For example it unclear if it is possible to visualize the textual information like on paper prints or on 2D displays. The current study empirically compares these types of different output mediums to advise rules for visualization of text in 3D Virtual Environments. Results show, that textual information has to be slightly enlarged for the 3D Virtual Environment. In addition, subjects performed better in conditions with projected textual information compared to real text.

Do We Need a New Internet for Elderly People? A Cross-Cultural Investigation

This paper describes the development of a culturally sensitive instrument for assessing user needs related to Internet usage. The resulting instrument, which encompasses four questionnaires used to obtain empirical data, was validated in a pre-study and experimental study in Germany and South Korea, and provides a quantitative and qualitative differentiation of the Internet needs of different groups. In a computer-based test, it was shown that the questionnaire tool allowed certain aspects of Internet usage to be predicted.

User experience starts at the keystroke level: the model of user experience (MUX)

In the last years the emotional impact of artifacts became more and more interesting to the field of human-computer interaction research. Despite many models that describe factors of user experience (UX), most of them are of a descriptive nature. In contrast, we propose a theoretical approach, the model of user experience (MUX) that offers an explanation for the emergence of UX starting from the very first interaction steps. Additionally, we present empirical results that support these assumptions of our theoretical approach that were under investigation. In detail we found that affordances as well as standard signals foster users performance on a small time scale (up to 3 sec.). However, these small changes affected peoples UX. Hence we conclude that it is a fruitful approach to start investigating UX on a keystroke level.

The influence of environmental factors on speed choice

Speed and homogeneity of speed are important factors for safe and sustainable traffic. Lower speeds and more homogeneous speeds are safer and cause less pollution. Speed behavior is influenced by environmental factors as well as by personal factors. Understanding the relation between speed behaviour and the influencing factors offers clues for appropriate countermeasures against inappropriate and excessive speed. This study investigates the relation between speed and environmental factors for single lane rural roads, one of the most hazardous road types in the Netherlands. The study uses data from two provincial road authorities. Data consists of speed data from loop detectors, road design characteristics, characteristics of the road environment, and police enforcement. The first objective of this study is to validate the outcomes of earlier studies reported in literature, such as photograph studies and self reported speed behaviour studies. In this study, the influence of the same external factors on percentile speed measures and homogeneity measures from speed loops are investigated. A second objective is to refine the credibility models by adding external factors, if relevant. The results of this study replicate some of the results that were found earlier, but not all. No additional factors were found; results and consequences will be discussed.

German taxi drivers' experiences and expressions of driving anger: Are the driving anger scale and the driving anger expression inventory valid measures?

ABSTRACT Objective: The objective of this article was 2-fold: firstly, we wanted to examine whether the original Driving Anger Scale (DAS) and the original Driving Anger Expression Inventory (DAX) apply to German professional taxi drivers because these scales have previously been given to professional and particularly to nonprofessional drivers in different countries. Secondly, we wanted to examine possible differences in driving anger experience and expression between professional German taxi drivers and nonprofessional German drivers. Methods: We applied German versions of the DAS, the DAX, and the State–Trait Anger Expression Inventory (STAXI) to a sample of 138 professional German taxi drivers. We then compared their ratings to the ratings of a sample of 1,136 nonprofessional German drivers (Oehl and Brandenburg n.d.). Results: Regarding our first objective, confirmatory factor analysis shows that the model fit of the DAS is better for nonprofessional drivers than for professional drivers. The DAX applies neither to professional nor to nonprofessional German drivers properly. Consequently, we suggest modified shorter versions of both scales for professional drivers. The STAXI applies to both professional and nonprofessional drivers. With respect to our second objective, we show that professional drivers experience significantly less driving anger than nonprofessional drivers, but they express more driving anger. Conclusions: We conclude that the STAXI can be applied to professional German taxi drivers. In contrast, for the DAS and the DAX we found particular shorter versions for professional taxi drivers. Especially for the DAX, most statements were too strong for German drivers to agree to. They do not show behaviors related to driving anger expression as they are described in the DAX. These problems with the original American DAX items are in line with several other studies in different countries. Future investigations should examine whether (professional) drivers from further countries express their anger as proposed by the DAX. In addition, professional drivers experience less driving anger (DAS) and less general trait anger (STAXI) than nonprofessional drivers, but they report more driving anger expression (DAX) and more current general state anger (STAXI). Subsequent studies should therefore focus on different types of anger within the group of professional drivers.

Zeitliche Verläufe emotionaler Aktivierung in der Mensch-Technik-Interaktion / Temporal dynamics of emotional activation in man-machine interaction

Zusammenfassung Bei der Interaktion mit technischen Geräten spielt das emotionale Nutzererleben (UX, User Experience) eine große Rolle. Die vorliegende Studie untersuchte zwei UX-Aspekte. Zum einen wurde die Möglichkeit der Induktion von Emotionen (Frustration und Freude) durch die Interaktion mit einer interaktiven Spielekonsole untersucht, zum anderen stand der Einfluss dieser Induktion auf die Touch-Interaktion mit einem Tablet im Fokus der Untersuchung. Die Studienergebnisse legen nahe, dass es möglich ist, mit einer interaktiven, bewegungsgesteuerten Spielekonsole gezielt distinkte Emotionen zu induzieren. Darüber hinaus zeigten sich eigene Dynamiken für Frustration und Freude innerhalb der nachfolgenden Interaktion mit dem Tablet-PC. Letztlich war die Emotionsinduktion jedoch nicht stabil genug, um die Leistungen im Kontext der Touch-Interaktion zu beeinflussen. Die Ergebnisse werden vor dem Hintergrund von emotionalen Dynamiken, contextual change und der UX-Forschung diskutiert. Summary User Experience (UX) plays an important role in human machine interaction. This investigation focuses on two different aspects of UX. On the one hand we wanted to induce two affective states (frustration and happiness) in a humanmachine interaction (HMI) setting using a bodily interactive game console. On the other hand we analyzed the effects of the elicited emotional activation on the interaction with another device (tablet-PC). The results imply that it is possible to induce distinct affective states with an interactive, full-body controlled HMI. Interestingly, happiness and frustration showed different activation patterns in the subsequent interaction with the tablet-PC. For example, happiness did not last as long as frustration did. Nevertheless, both activation patterns did not have any effect on the subjects’ performance with the tablet- PC, maybe due to unstably elicited emotions. These findings are discussed against the background of research regarding emotional dynamics, contextual change, and UX.

The Sooner the Better: Drivers’ Reactions to Two-Step Take-Over Requests in Highly Automated Driving

Driving behavior after take-over requests (TORs) is one of the most popular subjects in human factors re-search on highly automated driving. Many studies utilized one-step TOR procedures to prompt drivers to resume vehicle control. The present paper examines driver behavior when experiencing a two-step TOR procedure in different modalities. A two-step TOR gives drivers a choice to resume vehicle controls be-tween a warning (first step) and an alarm (second step). Our findings indicate that a substantial number of drivers resumes vehicle controls after the second step, resulting in a higher number of crashes. More generally, criticality of the driving situation increases with increasing reaction times. Driving and interview data suggest that step two of the TOR should be presented earlier. Alternatively, a multi-step TOR could be used to increase drivers’ situational awareness. Auditory TORs are associated with shorter reaction times than visual-auditory TORs. Implications on TOR design are discussed.

The Effects of Grid- and List Design of E-Commerce Result Lists on Search Efficiency and Perceived Aesthetics

E-commerce became very important in recent years. About 40% of the customers state that they prefer online shopping over retail shopping. When searching for items in an online shop, the appearing result lists are an important part of the users’ experience. The users’ experience, in turn, is a crucial factor for a business’ success. This online-study examines the search efficiency and perceived aesthetics of two different result list designs. A grid design, which shows more than one item in a row and a list design, which displays only one item per row. Participants completed a visual search task on a fictitious website using their own devices. Reaction times measured search efficiency and the VisAWI questionnaire assessed perceived aesthetics. Results showed that the grid design led to faster reaction times and higher values in perceived aesthetics than the list design. Implications of the results and future studies are discussed.

Common Challenges in Ethical Practice when Testing Technology with Human Participants: Analyzing the Experiences of a Local Ethics Committee

Abstract Ethical aspects are of key importance in research and the development of technical systems. They play a major role when the societal impact of innovative products and new technologies is considered. However, ethics are already essential during technology development, especially when testing these technologies with human participants. The latter is becoming increasingly important when applying for project funding and for publishing peer reviewed journal papers. Responding to these needs, a local ethics committee at the Department of Psychology and Ergonomics at Technische Universität Berlin was founded in 2009. In this paper, we present an analysis of common pitfalls and blind spots that were detected by reviewers of this ethics committee. We studied the reviews of 98 applications for ethical approval. Results show that researchers (a) often lack concrete knowledge about potential ethical issues of their research and (b) that they might benefit from convenient tools to address relevant ethical challenges at early stages of product design. Based on the results of our analysis, we propose a set of six simple rules that can help to detect and to overcome most of the frequently appearing ethical issues.