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Torbjorn Akerstedt - One of the best experts on this subject based on the ideXlab platform.

  • the effect of daylight versus darkness on driver sleepiness a driving Simulator Study
    Journal of Sleep Research, 2018
    Co-Authors: Christer Ahlstrom, Torbjorn Akerstedt, Anna Anund, Carina Fors
    Abstract:

    Driver sleepiness studies are often carried out with alert drivers during daytime and sleep-deprived drivers during night-time. This design results in a mixture of different factors (e.g. circadian ...

  • the effects of driving situation on sleepiness indicators after sleep loss a driving Simulator Study
    Industrial Health, 2009
    Co-Authors: Goran Kecklund, Torbjorn Akerstedt, Anna Anund, Albert Kircher, Andreas Tapani
    Abstract:

    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.

  • the alerting effect of hitting a rumble strip a Simulator Study with sleepy drivers
    Accident Analysis & Prevention, 2008
    Co-Authors: Anna Anund, Goran Kecklund, Torbjorn Akerstedt, Anna Vadeby, Magnus Hjalmdahl
    Abstract:

    A moving base driving Simulator experiment was carried out in order to investigate the effects of milled rumble strips on driver fatigue. There were rumble strips both at the edge line and centre line. Four different physical designs of milled rumble strips (yielding noise values from 1.5 to 16 dBA) and two placements on shoulder were used in the experiment. Sound and vibrations from real milled rumble strips were reproduced in the Simulator. In total 35 regular shift workers drove during the morning hours after a full night shift. The main results showed an increase in sleepiness indicators (EEG alpha/theta activity, eye closure duration, standard deviation of lateral position, subjective sleepiness) from start to before hitting the rumble strip, an alerting effect in most parameters (not subjective sleepiness) after hitting the strip. The alertness enhancing effect was, however, short and the sleepiness signs returned 5 min after the rumble strip hit. Essentially no effects were seen due to type of strip. It was concluded that various aspects of sleepiness are increased before hitting a rumble strip and that the effect is very short-lived. Type of strip, as used in the present Study did not have any effect.

  • Impaired alertness and performance driving home from the night shift: A driving Simulator Study
    Journal of Sleep Research, 2005
    Co-Authors: Torbjorn Akerstedt, Björn Peters, Anna Anund, Goran Kecklund
    Abstract:

    Driving in the early morning is associated with increased accident risk affecting not only professional drivers but also those who commute to work. The present Study used a driving Simulator to investigate the effects of driving home from a night shift. Ten shift workers participated after a normal night shift and after a normal night sleep. The results showed that driving home from the night shift was associated with an increased number of incidents (two wheels outside the lane marking, from 2.4 to 7.6 times), decreased time to first accident, increased lateral deviation (from 18 to 43 cm), increased eye closure duration (0.102 to 0.143 s), and increased subjective sleepiness. The results indicate severe postnight shift effects on sleepiness and driving performance.

Donald L Fisher - One of the best experts on this subject based on the ideXlab platform.

  • the effect of male teenage passengers on male teenage drivers findings from a driving Simulator Study
    Accident Analysis & Prevention, 2013
    Co-Authors: Marie Claude Ouimet, Anuj K Pradhan, Bruce G Simonsmorton, Gautam Divekar, Hasmik Mehranian, Donald L Fisher
    Abstract:

    Studies have shown that teenage drivers are less attentive, more frequently exhibit risky driving behavior, and have a higher fatal crash risk in the presence of peers. The effects of direct peer pressure and conversation on young drivers have been examined. Little is known about the impact on driving performance of the presence of a non-interacting passenger and subtle modes of peer influence, such as perceived social norms. The goal of this Study was to examine if teenagers would engage in more risky driving practices and be less attentive in the presence of a passenger (vs. driving alone) as well as with a risk-accepting (vs. risk-averse) passenger. A confederate portrayed the passenger's characteristics mainly by his non-verbal attitude. The relationship between driver characteristics and driving behavior in the presence of a passenger was also examined. Thirty-six male participants aged 16-17 years old were randomly assigned to drive with a risk-accepting or risk-averse passenger. Main outcomes included speed, headway, gap acceptance, eye glances at hazards, and horizontal eye movement. Driver characteristics such as tolerance of deviance, susceptibility to peer pressure, and self-esteem were measured. Compared to solo driving, the presence of a passenger was associated with significantly fewer eye glances at hazards and a trend for fewer horizontal eye movements. Contrary to the hypothesis, however, Passenger Presence was associated with waiting for a greater number of vehicles to pass before initiating a left turn. Results also showed, contrary to the hypothesis, that participants with the risk-accepting passenger maintained significantly longer headway with the lead vehicle and engaged in more eye glances at hazards than participants with the risk-averse passenger. Finally, when driving with the passenger, earlier initiation of a left turn in a steady stream of oncoming vehicles was significantly associated with higher tolerance of deviance and susceptibility to peer pressure, while fewer eye glances at hazards was linked to lower self-esteem. While the results of this Study were mixed, they suggest that the presence of a teenage passenger can affect some aspects of teenage driver behavior even in the absence of overt pressure and distraction. Results are discussed in relation to theoretical concepts of social influence and social facilitation models.

  • do advance yield markings increase safe driver behaviors at unsignalized marked midblock crosswalks driving Simulator Study
    Transportation Research Record, 2011
    Co-Authors: Radhameris A Gomez, Siby Samuel, Luis Roman Gerardino, Matthew R E Romoser, John Collura, Michael A Knodler, Donald L Fisher
    Abstract:

    In the United States, 78% of pedestrian crashes occur at noninter-section crossings. As a result, unsignalized, marked midblock crosswalks are prime targets for remediation. Many of these crashes occur under sight-limited conditions in which the view of critical information by the driver or pedestrian is obstructed by a vehicle stopped in an adjacent travel or parking lane on the near side of the crosswalk. Study of such a situation on the open road is much too risky, but Study of the situation in a driving Simulator is not. This paper describes the development of scenarios with sight limitations to compare potential vehicle-pedestrian conflicts on a driving Simulator under conditions with two different types of pavement markings. Under the first condition, advance yield markings and symbol signs (prompts) that indicated "yield here to pedestrians" were used to warn drivers of pedestrians at marked, midblock crosswalks. Under the second condition, standard crosswalk treatments and prompts were used to war...

Larsgunnar Nilsson - One of the best experts on this subject based on the ideXlab platform.

  • changes in driver behaviour as a function of handsfree mobile phones a Simulator Study
    Accident Analysis & Prevention, 1994
    Co-Authors: Larsgunnar Nilsson
    Abstract:

    The effects of a mobile telephone task on drivers' reaction time, lane position, speed level, and workload were studied in two driving conditions (an easy or rather straight versus a hard or very curvy route). It was predicted that the mobile telephone task would have a negative effect on drivers' reaction time, lane position, and workload and lead to a reduction of speed. It was also predicted that the effects would be stronger for the hard driving task. The Study was conducted in the VTI driving Simulator. A total of 40 subjects, experienced drivers aged 23 to 61, were randomly assigned to four experimental conditions (telephone and easy or hard driving task versus control and easy or hard driving task). Contrary to the predictions, the strongest effects were found when the subjects were exposed to the easy driving task. In the condition where drivers had to perform the easy driving task, findings showed that a mobile telephone task had a negative effect on reaction time and led to a reduction of the speed level. In the condition where drivers had to perform the hard driving task, findings showed that a mobile telephone task had an effect only on the drivers' lateral position. Finally, the mobile telephone task led to an increased workload for both the easy and the hard driving task. The results are discussed in terms of which subtask, car driving or telephone task, the subjects gave the highest priority. Some implications for information systems in future cars are discussed.

  • changes in driver behaviour as a function of handsfree mobile phones a Simulator Study
    Strategic Highway Research Program and Traffic Safety on Two Continents International Symposium 1991 Gothenburg Sweden, 1991
    Co-Authors: Larsgunnar Nilsson
    Abstract:

    The effects of a mobile telephone conversation on drivers' reaction time, lane position, speed level, and workload in two driving conditions (easy versus hard driving task) were studied in an advan ...

Anna Anund - One of the best experts on this subject based on the ideXlab platform.

  • the effect of daylight versus darkness on driver sleepiness a driving Simulator Study
    Journal of Sleep Research, 2018
    Co-Authors: Christer Ahlstrom, Torbjorn Akerstedt, Anna Anund, Carina Fors
    Abstract:

    Driver sleepiness studies are often carried out with alert drivers during daytime and sleep-deprived drivers during night-time. This design results in a mixture of different factors (e.g. circadian ...

  • the effects of driving situation on sleepiness indicators after sleep loss a driving Simulator Study
    Industrial Health, 2009
    Co-Authors: Goran Kecklund, Torbjorn Akerstedt, Anna Anund, Albert Kircher, Andreas Tapani
    Abstract:

    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.

  • the alerting effect of hitting a rumble strip a Simulator Study with sleepy drivers
    Accident Analysis & Prevention, 2008
    Co-Authors: Anna Anund, Goran Kecklund, Torbjorn Akerstedt, Anna Vadeby, Magnus Hjalmdahl
    Abstract:

    A moving base driving Simulator experiment was carried out in order to investigate the effects of milled rumble strips on driver fatigue. There were rumble strips both at the edge line and centre line. Four different physical designs of milled rumble strips (yielding noise values from 1.5 to 16 dBA) and two placements on shoulder were used in the experiment. Sound and vibrations from real milled rumble strips were reproduced in the Simulator. In total 35 regular shift workers drove during the morning hours after a full night shift. The main results showed an increase in sleepiness indicators (EEG alpha/theta activity, eye closure duration, standard deviation of lateral position, subjective sleepiness) from start to before hitting the rumble strip, an alerting effect in most parameters (not subjective sleepiness) after hitting the strip. The alertness enhancing effect was, however, short and the sleepiness signs returned 5 min after the rumble strip hit. Essentially no effects were seen due to type of strip. It was concluded that various aspects of sleepiness are increased before hitting a rumble strip and that the effect is very short-lived. Type of strip, as used in the present Study did not have any effect.

  • Impaired alertness and performance driving home from the night shift: A driving Simulator Study
    Journal of Sleep Research, 2005
    Co-Authors: Torbjorn Akerstedt, Björn Peters, Anna Anund, Goran Kecklund
    Abstract:

    Driving in the early morning is associated with increased accident risk affecting not only professional drivers but also those who commute to work. The present Study used a driving Simulator to investigate the effects of driving home from a night shift. Ten shift workers participated after a normal night shift and after a normal night sleep. The results showed that driving home from the night shift was associated with an increased number of incidents (two wheels outside the lane marking, from 2.4 to 7.6 times), decreased time to first accident, increased lateral deviation (from 18 to 43 cm), increased eye closure duration (0.102 to 0.143 s), and increased subjective sleepiness. The results indicate severe postnight shift effects on sleepiness and driving performance.

J G Bowsher - One of the best experts on this subject based on the ideXlab platform.

  • metal on metal hip Simulator Study of increased wear particle surface area due to severe patient activity
    Proceedings of the Institution of Mechanical Engineers Part H: Journal of Engineering in Medicine, 2006
    Co-Authors: J G Bowsher, Azad Hussain, P A Williams, J C Shelton
    Abstract:

    This Study investigated changes in metal-on-metal (MOM) hip wear and wear particle characteristics arising from a more aggressive patient activity level compared with normal walking. The test hypothesis was that 'severe'-gait conditions will change wear, wear particle sizes, and morphology owing to a decline in joint lubrication. Four carbon MOM hip bearings 40 mm high were subjected to normal-walking and fast-jogging simulations in an orbital hip joint Simulator with 25 per cent alpha-calf serum as a lubricant. Co-Cr-Mo wear particles were extracted using an enzymatic method, and prolate ellipsoid equations were used to estimate particle volume and surface area. Fast-jogging simulations generated a sevenfold increase in volumetric wear, a 33 per cent increase in mean wear particle size, and a threefold increase in the number of larger (needle) particles compared with walking. This resulted in a twentyfold increase in total wear particle surface area per 10(6) cycles compared with walking, thereby confirming our hypothesis. The clinical significance of this result suggests that highly active MOM patients may exhibit greater ion release than less active patients.

  • metal on metal hip Simulator Study of increased wear particle surface area due to severe patient activity
    Proceedings of the Institution of Mechanical Engineers. Part H Journal of engineering in medicine, 2006
    Co-Authors: J G Bowsher, Azad Hussain, P A Williams, J C Shelton
    Abstract:

    AbstractThis Study investigated changes in metal-on-metal (MOM) hip wear and wear particle characteristics arising from a more aggressive patient activity level compared with normal walking. The test hypothesis was that ‘severe’-gait conditions will change wear, wear particle sizes, and morphology owing to a decline in joint lubrication. Four carbon MOM hip bearings 40 mm high were subjected to normal-walking and fast-jogging simulations in an orbital hip joint Simulator with 25 per cent α-calf serum as a lubricant. Co-Cr-Mo wear particles were extracted using an enzymatic method, and prolate ellipsoid equations were used to estimate particle volume and surface area. Fast-jogging simulations generated a sevenfold increase in volumetric wear, a 33 per cent increase in mean wear particle size, and a threefold increase in the number of larger (needle) particles compared with walking. This resulted in a twentyfold increase in total wear particle surface area per 106 cycles compared with walking, thereby confi...