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Total results: 302

Driving with binocular visual field loss? A study on a supervised on-road parcours with simultaneous eye and head tracking

Year: 2014

Authors: E Kasneci,K Sippel, K Aehling, M Heister

Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs) that may critically interfere with quality of life and driving licensure. The aims of this study were (i) to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii) to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed) of ten patients with homonymous visual field defects (HP), including four patients with right (HR) and six patients with left homonymous visual field defects (HL), ten glaucoma patients (GP), and twenty age and gender-related ophthalmologically healthy control subjects (C) during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD) critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL) due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on the central area of the visual field than patients who failed the test. In addition, patients who passed the test performed more glances towards the area of their visual field defect. In conclusion, our findings support the hypothesis that the extent of visual field per se cannot predict driving fitness, because some patients with HVFDs and advanced glaucoma can compensate for their deficit by effective visual scanning. Head movements appeared to be superior to eye and shoulder movements in predicting the outcome of the driving test under the present study scenario.

19 versions available

Gaze guidance for the visually impaired

Year: 2014

Authors: TC Kübler,E Kasneci,W Rosenstiel

Visual perception is perhaps the most important sensory input. During driving, about 90% of the relevant information is related to the visual input [Taylor 1982]. However, the quality of visual perception decreases with age, mainly related to a reduce in the visual acuity or in consequence of diseases affecting the visual system. Amongst the most severe types of visual impairments are visual field defects (areas of reduced perception in the visual field), which occur as a consequence of diseases affecting the brain, e.g., stroke, brain injury, trauma, or diseases affecting the optic nerve, e.g., glaucoma. Due to demographic aging, the number of people with such visual impairments is expected to rise [Kasneci 2013]. Since persons suffering from visual impairments may overlook hazardous objects, they are prohibited from driving. This, however, leads to a decrease in quality of life, mobility, and participation in social life. Several studies have shown that some patients show a safe driving behavior despite their visual impairment by performing effective visual exploration, i.e., adequate eye and head movements (e.g., towards their visual field defect [Kasneci et al. 2014b]). Thus, a better understanding of visual perception mechanisms, i.e., of why and how we attend certain parts of our environment while 'ignoring' others, is a key question to helping visually impaired persons in complex, real-life tasks, such as driving a car.

3 versions available

Masking Action Relevant Stimuli in dynamic environments–The MARS method

Year: 2014

Authors: L Rittger,A Kiesel,G Schmidt, C Maag

We present the novel MARS (Masking Action Relevant Stimuli) method for measuring drivers’ information demand for an action relevant stimulus in the driving scene. In a driving simulator setting, the traffic light as dynamic action relevant stimulus was masked. Drivers pressed a button to unmask the traffic light for a fixed period of time as often as they wanted. We compared the number of button presses with the number of fixations on the traffic light in a separate block using eye tracking. For the driving task, we varied the road environment by presenting different traffic light states, by adding a lead vehicle or no lead vehicle and by manipulating the visibility of the driving environment by fog or no fog. Results showed that these experimental variations affected the number of button presses as dependent measure of the MARS method. Although the number of fixations was affected qualitatively similar, changes were more pronounced in the number of fixations compared to the number of button presses. We argue that the number of button presses is an indicator for action relevance of the stimulus, complementing or even substituting the recording and analyses of gaze behaviour for specific research questions. In addition, using the MARS method did not change dynamic driving behaviour and driving with the MARS method was neither disturbing, nor difficult to learn. Future research is required to show the generalisability of the method to other stimuli in the driving scene.

10 versions available

SteerPad Development and Evaluation of a Touchpad in the Steering Wheel from a User Experience Perspective

Year: 2014

Authors: V Swantesson, D Gunnarsson

Driver safety has since the birth of automobiles been paramount. In a time when technologies are changing the way people interact with the outside world, the vehicle industries need to keep up with these changes in terms of both safety and user experience. When trying to assess this complication, some of these technologies have been integrated into the cars, thus leading to more distractions while driving. This thesis describes this dilemma as the gap between automobile safety and in-vehicle infotainment. By the use of a touchpad installed on the right hand side of the steering wheel, the thesis has developed and evaluated a prototype interface that is located in the vehicles dashboard display with goals to lower driver distraction. This touchpad is developed with three main sources of interaction; swipes, tactile interaction and character recognition. By merging and combining these sources the thesis has successfully developed a test prototype to be used for evaluation. The prototype was tested against an already existing in-vehicle information system where a number of use cases and scenarios were used to test the systems in terms of usability and user experience. Guidelines on safety regulations set by NHTSA have been studied and applied to the projects development and user studies. Test results indicate that this technology has the potential to lower the driver distraction while still maintaining a high level of usability and user experience. Finally the thesis presents a number of suggestions and ideas in reference to further development and studies.

3 versions available

The impact of an anticipatory eco-driver assistant system in different complex driving situations on the driver behavior

Year: 2014

Authors: CP Rommerskirchen, M Helmbrecht

The anticipatory advanced driver assistance system (ADAS) developed at the Institute of Ergonomics at the TU München assists to reduce the individual fuel consumption of each driver by anticipating earlier. The goal is to achieve improvements in as many road situations as possible. The paper gives an overview on the different options to support the driver to reduce its fuel consumption. It also discusses the possibilities of an extension of anticipation to support the driver in eco-driving. Related work shows that anticipatory advanced driver assistance systems help to save fuel, but they focus on the general potentials of the system. The presented study in this paper, however, deals with the question of the impact of different road traffic situations on an anticipatory driver assistance system. Different traffic scenarios were chosen and varied in its complexity to evaluate the impact of the complexity of different driving situations on an anticipatory ADAS. A driving simulator study was conducted with 27 participants. The results showed that the fuel consumption is reduced with the assistant system due to earlier and better reaction but that there is no influence of the complexity of a situation on that. The influence of the situation on the driver in his use of the ADAS can be shown by his visual behavior. The percentage of the gaze time on the human machine interface (HMI) on the system is significantly reduced in the more complex situations.

7 versions available

Traffic light assistant-what the users want

Year: 2014

Authors: M Krause, A Rissel,K Bengler

In a driving simulator experiment, a prototypical traffic light phase assistant is assessed. The main research issue: How would a user customize the system? As a sideline, data is gathered with a special Detection Response Task (DRT), the Tactile Detection Task (TDT), in conjunction with an auditory cognitive task as reference. Recorded gaze data, driving behavior, subjective ratings with a System Usability Scale (SUS) and an AttrakDiff2 -questionnaire are also reported. The subjects were able to customize ten parameters of the traffic light assistant system. The so personalized system configuration showed no great enhancement in the subjective ratings; thus, the later application implementation will include only little configuration features for the user. However, the test persons exhibited a willingness to be informed about speeding by a speed alerting function within the traffic light assistant system. The performance (reaction time) of the TDT is interpreted as a measure for the cognitive load while using the interface. The auditory cognitive task prolonged the reaction times for a tactile detection task more than the traffic light information system. The glance times are in line with current guidelines and the driving behavior shows a potential benefit for safety. Thus, the reported experiment evaluates an interface for use while driving with objective metrics regarding distraction and subjective results related to usability and joy-of-use.

4 versions available

Wayfinding decision situations: A conceptual model and evaluation

Year: 2014

Authors: I Giannopoulos,P Kiefer,M Raubal,KF Richter

Humans engage in wayfinding many times a day. We try to find our way in urban environments when walking towards our work places or when visiting a city as tourists. In order to reach the targeted destination, we have to make a series of wayfinding decisions of varying complexity. Previous research has focused on classifying the complexity of these wayfinding decisions, primarily looking at the complexity of the decision point itself (e.g., the number of possible routes or branches). In this paper, we proceed one step further by incorporating the user, instructions, and environmental factors into a model that assesses the complexity of a wayfinding decision. We constructed and evaluated three models using data collected from an outdoor wayfinding study. Our results suggest that additional factors approximate the complexity of a wayfinding decision better than the simple model using only the number of branches as a criterion.

11 versions available

An investigation into control mechanisms of driving performance: resource depletion and effort-regulation

Year: 2013

Authors: TL Louw

Driver fatigue is a complex phenomenon that has a range of causal factors including sleep-related and task-related factors. These manifest as different safety and performance outcomes. Extensive research has been applied to linking these factors to performance impairment. However, little research focuses on the mechanisms by which this link exists. This research project therefore focuses on the processes underlying how driving performance is controlled and maintained during the development on non-sleep-related driver fatigue. The main aim was to establish whether progressive impairment of driving control over a prolonged drive could be attributed to a depletion of attentional resources, as proposed by Resource Theory, or to a withdrawal of effort, as proposed by Effort-Regulation Theory. As a multi-component skill, driving requires perception, cognition and motor output. The secondary aim of this research was therefore to assess whether a prolonged drive impairs stage-specific information processing. Participants (n=24) in three experimental groups performed a 90-minute simulated drive wherein they were expected to keep the bonnet of a car on a lane (tracking task). The three groups differed in terms of lane width: small, medium and large, corresponding to low, medium, and high task-demand, respectively. To assess the impacts of this task on stage-specific information processing, participants performed a set of resource specific tests before and after the prolonged drive. Each task had two difficulty variations to ensure that performance decrement was due not only to the task-characteristic, but specifically to resource depletion. The tests probing information processing were: a modified Fitts’ tapping task for motor programming, a digit recall task for perception, and an object recognition reading task for cognition. Performance was measured as lateral deviation of the car. Physiological measures included heart rate frequency (HR) and various time- and frequency-domain heart rate variability (HRV) parameters, eye blink frequency and duration. The Borg CR-10 scale was used to evaluate subjective effort and fatigue during the task. Driving control declined over time and was supplemented by HR, HRV, blink frequency and duration, indicating an increase in parasympathetic activity (or a reduction in arousal). An increase in blink frequency was considered as a sign of withdrawal of attentional resources over time. Driving control declined to a greater extent in the large road width group and reflected a lower parasympathetic activity, whereas the inverse was observed for the small road width group. Resource tests reveal a non-specific impairment of information processing following the prolonged drive. However, this was accompanied by an increase in parasympathetic activity. Overall, results indicate that Effort-Regulation Theory better accounts for the impairment of driving control in prolonged driving than does Resource Theory. This suggests that the impact of fatigue is guided more by task goals and intrinsic motivation than by the manner in which the fatigue state developed. Moreover, performance impairment by effort-regulation is dependant more on time on task than on task-demand.

3 versions available

D9. 3-Requirements & Specification & first Modelling for the Automotive AdCoS and HF-RTP Requirements Definition Update (Feedback)

Year: 2013

Authors: FT CRF, EL REL, T Bellet, JC Bornard, D Gruyer

The main objective of WP9 is the development and qualification of AdCoS in Automotive (AUT) domain using the tailored HF-RTP and methodology from WP1, to demonstrate the added value for industrial engineering processes, in terms of reduced cost, fewer necessary development cycles and better functional performances. This report describes the requirements, specifications and the first modelling for the AdCoS applications in the Automotive (AUT) domain, with reference to the target-scenarios (TSs) and the Use-cases (UCs) described in the deliverable D9.1 “Requirements Definition for the HF-RTP, Methodology and Techniques and Tools from an Automotive Perspective”. In particular, we mainly refer to the two AdCoS applications implemented on the real test-vehicles (TVs): • Adapted Assistance, that is a Lane-Change Assistant (LCA) system, led by the CRF partner. • Adapted Automation, that is an automatic Intuitive Driving (ID) system, led by the IAS partner. In addition, this report includes the results of a first attempt to model the AdCoS using the HF-RTP and methodology utilising either pre-existing tools or new tools to be developed in the frame of the HoliDes project. Section §2 contains a list of tools definitely applied from WP1-5. Section §3 describes each AdCoS use case including AdCoS operational definitions, HMI for the AdCoS, tools applied from the HF-RTP, requirements and specifications, and the system architecture. Section §4 reports on feedback from WP 1-5. Section §5 presents some conclusions and the next steps.

1 version available:

Dynamic simulation and prediction of drivers’ attention distribution

Year: 2013

Authors: B Wortelen,M Baumann,A Lüdtke

The distribution of driver’s attention is a crucial aspect for safe driving. The SEEV model by Wickens is a state of the art model that provides an easy but abstract way to estimate the distribution of attention for specific situations. The present paper presents an extension of the SEEV model, the Adaptive Information Expectancy (AIE) model. The AIE model is a sophisticated model of attention control, able to provide estimates based on a far more detailed simulation of human allocation of attention within a cognitive architecture. The AIE model relates attention directly to a task model, which is executed within the architecture. It is able to automatically measure task-dependent event frequencies and adapt its distribution of attention according to these frequencies. The AIE model was used to create a dynamic cognitive driver model. A driving simulator study with 21 participants has been conducted to evaluate the predictions of the driver model. Event rates for the primary driving task and an artificial secondary task have been varied, as well as the priorization of tasks. Both the SEEV and the AIE model provided estimates for percentage dwell times with similar quality, while the AIE model was able to provide estimates for further measure like gaze frequencies and link values.

8 versions available