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  • 1.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Considerations when calculating percent road centre from eye movement data in driver distraction monitoring2009In: Proceedings of the Fifth International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design, 2009, p. 132-139Conference paper (Refereed)
    Abstract [en]

    Percent road center (PRC) is a performance indicator which is sensitive to driver distraction. The original definition of PRC is based on fixation data extracted from eye movement recordings, but it has also been suggested that PRC can be determined directly from the gaze data without segmenting it into saccades and fixations. The primary aim of this paper is to investigate if this is the case.

    Naturalistic driving data from a small scale field operational test comprising seven vehicles was used in the evaluation. It was found that PRC time traces based on gaze data and fixation data, respectively, were highly similar (correlation coefficient=0.95, average wavelet semblance=0.84) except for an absolute amplitude difference of about 8%. This indicates that the two approaches can be used interchangeably and that the processing step of segmenting gaze data into saccades and fixations can be left out.

    In addition to this finding, design issues related to the calculation of PRC are investigated. Especially, the impact of gaze cases pointing towards the intersection of the road centre area and the centre rear mirror were investigated. Results lead to conclude that gazes and fixations on the centre rear mirror should be removed from the PRC calculations, as they may negatively influence the correctness of the performance indicator.

  • 2.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholm university, Stress research institute.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics.
    Åkerstedt, Torbjörn
    Karolinska institutet, Clinical neuroscience.
    The effects of driving situation on sleepiness indicators after sleep loss: A driving simulator study2009In: Industrial Health, ISSN 0019-8366, E-ISSN 1880-8026, Vol. 47, no 4, p. 393-401Article in journal (Refereed)
    Abstract [en]

    Almost all studies of sleepy driving are carried out in driving simulators and with monotonous road conditions (no interaction with other cars). The present study investigated indicators of sleepy driving in a more challenging scenario after a night awake. 17 participants drove a high fidelity moving base driving simulator experiment while sleepiness was monitored physiologically and behaviourally. Short periods of situations of free driving (no other vehicles) alternated with short periods of following another vehicle (car following) with and without the possibility to overtake. The result showed that a night of prior sleep loss increased sleepiness levels at the wheel (eye closure duration and lateral variability) compared to after a night of normal sleep. Blink duration while overtaking was significantly lower compared to the other situations, it was at the same level as after night sleep. Speed when passing a stopped school bus was not significantly affected by sleepiness. However the warning caused a more rapid reduction of speed. In conclusion, a moderately challenging driving contest did not affect sleepiness indicators, but a very challenging one did so (overtaking). This suggests that it is important to monitor the driving situation in field operational tests of sleepy driving.

  • 3.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute.
    Tapani, Andreas
    Swedish National Road and Transport Research Institute.
    The effect of milled rumble strips versus virtual rumble strips on sleepy drivers: a driving simulator study2009Report (Other academic)
    Abstract [en]

    The aim of the EU project IN-SAFETY is to create effective combinations of traditional infrastructure measures combined with new technology to increase the self-explanatory and forgiving nature of the road traffic system. This report describes the method, results and conclusions of a driving simulator experiment with the aim to evaluate the effect of two scenarios of importance selected on a theoretical framework within IN-SAFETY: lane departure warning in terms of milled rumble strips or as a driver support system, and the effect of an in-vehicle warning system informing there is a school bus ahead, simulating a system based on vehicle to vehicle information. Concerning the "lane departure warning", the experiment considered possibilities and consequences of replacing the infrastructure element milled rumble strips with a haptic in-vehicle system. Both centre and side line rumble strips on a two-lane highway were studied and compared with a baseline. In-vehicle "School bus ahead warning" was considered as an example of in-vehicle information used to inform the driver of upcoming events. Both rumble strips and school bus warning was studied for drivers after not having slept the night before driving as well as after a night's sleep in order to investigate consequences of driver state on system effectiveness. The results showed that there is a potential to substitute the infrastructure measure rumble strips with an in-vehicle assistance system. Moreover, in-vehicle information was found to be an effective way of reducing the subjects' speeds during temporary critical situations concerning traffic safety.

  • 4.
    Kircher, Albert
    et al.
    Swedish National Road and Transport Research Institute.
    Uddman, Marcus
    Virtual Technology.
    Sandin, Jesper
    Virtual Technology.
    Vehicle control and drowsiness2002Report (Other academic)
    Abstract [en]

    The report consists of two parts. The first part is a literature study aimed at identifying the most relevant indicators for predicting and detecting fatigue induced impaired driving. The aim was to identify possible performance based technologies, such as the lateral control of the car. Thus, less attention was devoted to e.g. psycho-physiological measures like EEG. A large number of research reports describing various approaches have been reviewed. The survey clearly indicates that no single indicator can be used to detect drowsy driving.A combination of different measures is recommended e.g. analysis of lateral control performance and eye blink pattern. Furthermore, it should be noted that so far there is no commercial system available that provides a sufficiently reliable method to detect a drowsy driver. In the second part, experimental data from previous driving simulator experiments were analysed by means of signal processing and statistical analyses. Specific attention was paid to investigate the potential of lateral vehicle position data as a mean to estimate driver drowsiness. The analysis of experimental data did not reveal any clear answer to what indicators are the most prominent with respect to detect drowsy driving behaviour. Further investigations and analyses of driving behaviour data are needed. However, the data analysis conforms in large to the findings in the literature survey.

  • 5.
    Kircher, Albert
    et al.
    Swedish National Road and Transport Research Institute.
    Vogel, Katja
    Swedish National Road and Transport Research Institute.
    Törnros, Jan
    Swedish National Road and Transport Research Institute.
    Bolling, Anne
    Swedish National Road and Transport Research Institute.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute.
    Patten, Christopher
    Swedish National Road and Transport Research Institute.
    Malmström, Therese
    Ceci, Ruggero
    Mobile telephone simulator study2004Report (Other academic)
    Abstract [sv]

    The study consists of four separate experiments conducted in the VTI driving

    simulator. The common theme was to investigate how driver behaviour and

    traffic safety are influenced when the driver attends to another technical

    device while driving. The experiments were concerned with handsfree or

    handheld mobile phone conversation and dialling, receiving mobile phone SMS

    messages and watching a DVD film (the latter two being minor pilot

    experiments). In three of the experiments (mobile phone conversation, SMS,

    DVD) the participants drove a route which led through urban and rural

    environments, ranging from 90 km/h rural to 50 km/h urban environments. The

    urban environments differed in complexity (three levels). The driving

    distance was about 70 km. The dialling experiment used a rural environment

    with a speed limit of 110 km/h. The driving distance was about 15 km. In the

    main experiment dealing with mobile phone conversation, a number of driving

    performance measures were analysed: driving speed, variation in lateral

    position, deceleration, brake reaction time, headway, time to collision, etc.

    PDT (Peripheral Detection Task) was used as a measure of mental workload.

    Mobile phone conversation was found demanding in terms of mental workload. It

    also had effects on driving. Most effects were quite similar for the two

    phone modes (handsfree, handheld). Impaired reaction time performance was

    demonstrated in one of the situations for handheld mode. However, effects

    were found which could be interpreted as attempts to compensate for the

    increased workload caused by the mobile phone conversation: speed was reduced

    (more so for handheld than for handsfree mode), and time and distance headway

    increased. In spite of these compensatory behaviours, mental workload was

    still markedly increased by phone use. In the SMS experiment the participants

    braked later in one situation when reading the SMS message. No other effects

    were found in this minor experiment. In the DVD experiment, mental workload

    increased when watching the film, although this was compensated for to some

    extent by the increased distance headway to a lead vehicle. No compensation

    in terms of reduced driving speed, however, was apparent in this experiment.

    In the dialling experiment negative effects on traffic safety were evident

    from the larger variance of lateral car position during the dialling task for

    the handsfree phone mode. The mental workload also increased with the

    dialling task. Compensation in terms of reduced driving speed was apparent

    for both phone modes. Other aspects of mobile phone use while driving still

    remain to be analysed in more detail, such as starting or finishing a call,

    looking for a phone number to dial, mishaps like dropping the phone, etc.

  • 6.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Comparison of two eye-gaze based real-time driver distraction detection algorithms in a small-scale field operational test2009In: Proceedings of the 5th International Driving Symposium on Human Factors in Driver Assessment and Design, 2009, p. 16-23Conference paper (Refereed)
    Abstract [en]

    Driver distraction is a field which has received increasing attention in the last years, especially after it became evident that distraction is a major factor contributing to road casualties. Monitoring, detecting and limiting driver distraction could contribute significantly to improve road traffic safety. With the introduction of novel unobtrusive gaze-tracking systems real-time algorithms based on the driver’s gaze direction can be developed for driver distraction warning systems.

    The study describes and compares two different algorithms for gaze-based driver distraction detection based on the eye tracking data obtained in a field study. One algorithm relies on the metric “percent road centre” of gaze direction, the other on gaze zones in the vehicle. Results show that both algorithms have potential for detecting driver distraction, but that no effect of the distraction warnings on attention as defined by the algorithms could be observed.

  • 7.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    The relationship between glance direction and eye tracking quality based on data from a long-term field study2009In: ITS in Daily Life, Stockholm, 2009Conference paper (Refereed)
    Abstract [en]

    It has been shown that distraction is a major factor contributing to road casualties. Detecting and limiting driver impairment could improve road safety. With the introduction of unobtrusive gaze-tracking systems gaze based real-time algorithms can be developed for driver state monitoring.

    The data reported here stem from an extended field study, during which seven drivers used an instrumented car for one month each. Eye tracking quality is best when the gaze is directed to the road center. The head tracking data show a bimodal distribution, which is interpreted as the drivers’ leaning the head against the head rest at times.

  • 8.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Results of a field study on a driver distraction warning system2009Report (Other academic)
    Abstract [sv]

    The main goal of the distraction and drowsiness field study was to evaluate a system for detecting driver distraction and drowsiness. This report focuses on the results of the study, indicating how a distraction warning system influenced glance behaviour. A vehicle was instrumented with an automatic eye tracker and other sensors. Seven participants drove the vehicle during one month each. During the first ten days a baseline was collected. Afterwards the warnings were activated, which involved that the drivers received a vibration in the seat when the algorithm determined that they had looked away from the forward roadway for a too long time. The main finding was that the drivers' gaze behaviour was not influenced much by the distraction warnings. The drivers received distraction warnings at about the same frequency during the treatment and the baseline phase. Performance indicators like "percent road centre" and others did not change from baseline to treatment phase. The average percentage of very long glances decreased slightly in the treatment phase, suggesting that the warning had an effect on the more extreme glance behaviour. There are also indications that the system helped prevent further extended glances away from the road immediately after a warning was issued.

  • 9.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Claezon, Fredrich
    Saab Automobile.
    Distraction and drowsiness - a field study: technical report2009Report (Other academic)
    Abstract [en]

    The main goal of the distraction and drowsiness field study was to evaluate a system for detecting driver distraction and drowsiness. This report focuses on the system implementation and the algorithms detecting distraction and drowsiness. A vehicle was instrumented with video cameras, an automatic eye tracker and GPS receivers. Further data were read from the CAN bus of the car. The data were logged continuously with high frequency. The log system operated autonomously. Seven participants drove the vehicle during one month each. During the first ten days a behavioural baseline was collected. Afterwards the warnings were activated, such that the drivers received distraction warnings in form of a vibration in the seat when the algorithm determined that they had looked away from the forward roadway too much. A separate algorithm judged whether the drivers were drowsy or not. Questionnaires were administered on three occasions during the course of the study. No major problems were encountered during the field operational test (FOT), but a number of smaller problems had to be solved. However, in the end of the data collection period the computer installed in the car became more and more unstable, which led to increased data loss.

  • 10.
    Kircher, Katja
    et al.
    Swedish National Road and Transport Research Institute.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute.
    Kircher, Albert
    Swedish National Road and Transport Research Institute.
    Falkmer, Torbjörn
    Swedish National Road and Transport Research Institute.
    Anund, Anna
    Swedish National Road and Transport Research Institute.
    Passering av buss i 30 km/h: utvärdering av säkerhetseffekter i samband med hastighetsgräns 30 km/h vid passering av buss - en simulatorstudie2007Report (Other academic)
    Abstract [sv]

    A simulator study was conducted to investigate the implementation of a new law which prescribes a speed limit of 30 km/h when passing buses equipped with a 30-sign and flashing lights. It was shown that the drivers follow the rule better when they pass a bus on their own side than when the bus was standing on the opposite side of the road. The slowest mean speeds were found when passing a bus on a road with a speed limit of 70 km/h. The highest speed reduction, however, was found when the posted speed limit was 90 km/h. A bus without signage did not induce the same speed reduction as a bus with signage, which means that the drivers were aware of the meaning of the signage. Driving behaviour showed that the flashing lights are of importance, because the drivers in the study started braking before the 30-sign was readable.

  • 11.
    Linder, Astrid
    et al.
    Swedish National Road and Transport Research Institute.
    Kircher, Albert
    Swedish National Road and Transport Research Institute.
    Vadeby, Anna
    Swedish National Road and Transport Research Institute.
    Nygårdhs, Sara
    Swedish National Road and Transport Research Institute.
    Intelligent Transport Systems (ITS) in passenger cars and methods for assessment of traffic safety impact: a literature review2007Report (Other academic)
    Abstract [en]

    The background for this study is that many Intelligent Transport Systems (ITS) are currently introduced in passenger vehicles aiming at providing increased traffic safety. This provides a need to assess the traffic safety effects from these systems. The question that this report highlights is how these systems are designed and how the effects are evaluated. The review resulted in identification of 300 references of which the most relevant are found in this report. The report contains a description of the background of why and how 20 systems or groups of systems have been developed, in which vehicles they can be found, a short technical description of how they work, publication of traffic safety effects and future development plans. Regarding statistical methods, an overview of how they work and the results when using these methods on ITS are described. In addition, the report contains a summary of ways of assessing safety effects from areas such as food, nuclear power and pharmaceutical industries. The conclusion is that there are currently many different ways of supporting the driver in the task of driving the vehicle. Regarding the impact on traffic safety of these systems it is still an open question which evaluation methods to use.

  • 12.
    Lützhöft, Margareta
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Albert
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Gillberg, Mats
    Karolinska institutet.
    Fatigue at sea: a field study in Swedish shipping2007Report (Other academic)
    Abstract [en]

    The purpose of this study was to collect data about the fatigue level of bridge watch keepers to use for revising earlier sleep models, and devise innovative solutions for the shipping industry. Data collection included interviews with shipping companies and a field study onboard 13 cargo vessels. 32 participants took part in representing two watch systems; 2-watch and 3-watch. Subjective sleepiness and stress estimations were performed once every hour. Electrooculography was used to record eye movement behaviour. Reaction time test was made to examine performance. 3-watch participants are more satisfied with their working hours and working situation. Tendencies indicate that 2-watch participants are a bit more tired, whereas the stress is the same. All are less sleepy and less stressed at home. Time on shift had effect on sleepiness. The highest Karolinska Sleepiness Scale scores were recorded in the late night and early morning. After night shift the reaction times have higher variance and more long reaction times are present. The mean value after night shift was significantly higher than after day shift. All thirteen shipping agreed that officers on the bridge always have tasks sensitive to fatigue but no company experienced fatigue as a problem during normal conditions. All were positive to monitoring devices, mentioning safety matters.

  • 13.
    Vogel, Katja
    et al.
    Swedish National Road and Transport Research Institute.
    Kircher, Albert
    Swedish National Road and Transport Research Institute.
    Alm, Håkan
    Linköpings Universitet.
    Nilsson, Lena
    Swedish National Road and Transport Research Institute.
    Traffic sense: which factors influence the ability to predict the development of traffic scenes?2003In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 35, no 5, p. 749-762Article in journal (Refereed)
    Abstract [en]

    A study was conducted to evaluate the skill to predict the development of traffic situations. A stop-controlled intersection was filmed over several days, and 12 scenes with varying traffic complexity were selected. In half of the scenes, the traffic rules were violated, in half of the scenes, the rules were observed. A total of 36 participants were asked to watch the scenes and predict how the scene would most likely develop in the 2 s after the film was paused. Additionally, the participants rated how certain they were about their prediction, and how complex and dangerous they assessed the scenes to be. With the method used here, experienced drivers were not found to make more correct predictions of situational development, and no difference in skill to predict could be found between genders. Nevertheless, more experienced drivers were more certain in their judgements and evaluated the situations on average as less complex and dangerous than did less experienced drivers. Scenes in which the traffic rules were violated were more difficult to predict correctly. The scenes in which the participants predicted violations were rated as more complex and dangerous. It is concluded that the low-cost method used here is more useful for examining which scenes are generally easy or difficult to predict and how they are experienced subjectively than to investigate differences in performance for different driver categories.

1 - 13 of 13
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