| 1. |
- Ahlström, Christer, et al.
(författare)
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Dangerous use of mobile phones and other communication devices while driving : A toolbox of counter-measures
- 2013
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Ingår i: Proceedings of the 16th International Conference Road Safety on Four Continents. - Linköping : Statens väg- och transportforskningsinstitut.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of mobile phone and similar devices while driving has been a topic of discussion and research for several years. It is now an established fact that driving performance is deteriorated due to distraction but no clear conclusions can yet be drawn concerning influence on crash rates. Better studies on this relationship is needed. Most countries in Europe and many countries elsewhere have introduced different types of bans for handheld devices. Sweden has, however, no such bans. VTI was commissioned by the Swedish Government to outline possible means to reduce the dangerous usage of mobile phones and other communication devices while driving as alternatives to banning. This task was a result of a previous VTI-state-of-the-art review of research on mobile phone and other communication device usage while driving. One of the findings in the review was that bans on handheld phones did not appear to reduce the number of crashes.Eighteen different countermeasures in three main areas were suggested. (1) Technical solutions such as countermeasures directed towards the infrastructure, the vehicle and the communication device. (2) Education and information, describing different ways to increase knowledge and understanding among stakeholders and different driver categories. (3) Different possibilities for how society, industry and organisations can influence the behaviour of individuals, via policies, rules, recommendations and incentives. Our conclusion is that a combination of different countermeasures is needed – where education and information to the drivers are combined with support and incentives for a safe usage of different communication devices.
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| 2. |
- Ahlström, Christer, et al.
(författare)
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Fit-for-duty test for estimation of drivers sleepiness level: Eye movements improve the sleep/wake predictor
- 2013
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Ingår i: Transportation Research Part C. - : Elsevier. - 0968-090X .- 1879-2359. ; 26, s. 20-32
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Tidskriftsartikel (refereegranskat)abstract
- Driver sleepiness contributes to a considerable proportion of road accidents, and a fit-for-duty test able to measure a drivers sleepiness level might improve traffic safety. The aim of this study was to develop a fit-for-duty test based on eye movement measurements and on the sleep/wake predictor model (SWP, which predicts the sleepiness level) and evaluate the ability to predict severe sleepiness during real road driving. Twenty-four drivers participated in an experimental study which took place partly in the laboratory, where the fit-for-duty data were acquired, and partly on the road, where the drivers sleepiness was assessed. A series of four measurements were conducted over a 24-h period during different stages of sleepiness. Two separate analyses were performed; a variance analysis and a feature selection followed by classification analysis. In the first analysis it was found that the SWP and several eye movement features involving anti-saccades, pro-saccades, smooth pursuit, pupillometry and fixation stability varied significantly with different stages of sleep deprivation. In the second analysis, a feature set was determined based on floating forward selection. The correlation coefficient between a linear combination of the acquired features and subjective sleepiness (Karolinska sleepiness scale, KSS) was found to be R = 0.73 and the correct classification rate of drivers who reached high levels of sleepiness (KSS andgt;= 8) in the subsequent driving session was 82.4% (sensitivity = 80.0%, specificity = 84.2% and AUC = 0.86). Future improvements of a fit-for-duty test should focus on how to account for individual differences and situational/contextual factors in the test, and whether it is possible to maintain high sensitive/specificity with a shorter test that can be used in a real-life environment, e.g. on professional drivers.
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| 3. |
- Anund, Anna, et al.
(författare)
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Observer Rated Sleepiness and Real Road Driving : An Explorative Study
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:5, s. e64782-
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to explore if observer rated sleepiness (ORS) is a feasible method for quantification of driver sleepiness in field studies. Two measures of ORS were used:one for behavioural signs based on facial expression, body gestures and body movements labelled B-ORS, andone based on driving performance e.g. if swerving and other indicators of impaired driving occurs, labelled D-ORSA limited number of observers sitting in the back of an experimental vehicle on a motorway about 2 hours repeatedly 3 times per day (before lunch, after lunch, at night) observed 24 participant's sleepiness level with help of the two observer scales. At the same time the participant reported subjective sleepiness (KSS), EOG was recorded (for calculation of blink duration) and several driving measure were taken and synchronized with the reporting.Based on mixed model Anova and correlation analysis the result showed that observer ratings of sleepiness based on drivers' impaired performance and behavioural signs are sensitive to extend the general pattern of time awake, circadian phase and time of driving. The detailed analysis of the subjective sleepiness and ORS showed weak correspondence on an individual level. Only 16% of the changes in KSS were predicted by the observer. The correlation between the observer ratings based on performance (D-ORS) and behavioural signs (B-ORS) are high (r =. 588), and the B-ORS shows a moderately strong association (r =. 360) with blink duration. Both ORS measures show an association (r>0.45) with KSS, whereas the association with driving performance is weak.The results show that the ORS-method detects the expected general variations in sleepy driving in field studies, however, sudden changes in driver sleepiness on a detailed level as 5 minutes is usually not detected; this holds true both when taking into account driving behaviour or driver behavioural signs.
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| 4. |
- Fors, Carina, et al.
(författare)
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Investigation of driver sleepiness in FOT data : final report of the project SleepEYE II, part 2
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Driver sleepiness contributes to a great number of motor vehicle accidents every year. In order to reduce the number of sleepiness related accidents, more knowledge on e.g. prevalence, countermeasures and driver behaviour is needed. Data from field operational tests (FOT) has a potential to provide such knowledge with high ecological validity. The objective of the project was to propose and evaluate methods for identification of driver sleepiness in FOT data. More specifically, the aim was to identify objective indicators of sleepiness – based on driving behaviour, eye blink behaviour and models of circadian rhythm – and to evaluate a subjective video scoring method for estimating driver sleepiness levels. Data from two separate projects were used: 1) the ViP-project SleepEYE, in which a controlled field test was conducted, and 2) euroFOT, which was a large scale FOT. In a first step the data quality of blink-based indicators obtained from a camera system was evaluated. It was concluded that the data quality had to be improved and thus, a new detection algorithm was devised and implemented. The new detection algorithm had an acceptable detection rate (approximately 50 %) when applied to data from the SleepEYE field test, but for euroFOT data the number of identified blinks was very low (< 5 blinks/min) in about half of the trips. There is thus a need for further improvements of the blink detection algorithm. An in-depth study on indicators of driver sleepiness was carried out using data collected in the SleepEYE experiment, with the purpose of employing the best indicators to study driver sleepiness in the euroFOT database. The most promising indicators were found to be mean blink duration and number of line crossings. A sleepiness classifier was suggested based on the distribution of the data (i.e. visual inspection). When applied to SleepEYE data the classifier was found to have good specificity while the sensitivity of the classifier was not so good. From euroFOT no true data on the drivers’ sleepiness levels were available and it was therefore not possible to evaluate the performance of the classifier. However, an explorative analysis showed that only very few data points were classified as sleepy. This may be reasonable since most trips were conducted during daytime, but it is a somewhat disappointing result for the project. A study was carried out on whether it is possible to use video recordings of drivers in order to estimate the drivers’ self-rated level of sleepiness. Forty participants rated 54 one-minute video clips of an equal number of sleepy and alert drivers on a scale with three levels (alert, first signs of sleepiness, very sleepy). The results of the study showed that performing such observer rated sleepiness (ORS) estimations on drivers is extremely difficult. The videos available in FOTs are usually of rather poor quality which, clearly limits the possibility of making reliable observer rated sleepiness estimations. In conclusion, studying driver sleepiness in (existing) FOT data is difficult, for several reasons: 1) eye camera based indicators suffer from detection errors and low detection rate, 2) driving-based indicators are influenced by e.g. road curvature and traffic density, 3) models of sleepiness cannot be used since no information on hours slept and time awake is available, and 4) video scoring is not reliable, at least not given the quality of the available video recordings. In future studies on driver sleepiness in FOTs sleepiness should be addressed in the FOT design. Some information about the drivers' sleep and sleepiness (ratings, sleep diaries, etc.) must be collected during the test; otherwise it will be very difficult to get any useful results.
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| 5. |
- Fors, Carina, et al.
(författare)
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Simulator validation with respect to driver sleepiness and subjective experiences : final report of the project SleepEYE II, part 1
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the previous project SleepEYE, which aimed at developing tools for driver sleepiness detection, two experiments were carried out. In the first experiment, 18 drivers conducted two driving sessions on a motorway: one during daytime (alert) and one at night (sleep deprived). Sixteen of the drivers participated in the second experiment, which was similar to the first one, except that the driving sessions were conducted in an advanced moving base driving simulator. In the present study, the validity of the simulator was assessed using data that was collected in the two experiments. The validation analysis had three focuses: 1) general driver and driving behaviour related to driver sleepiness, 2) speed profile at change in posted speed limit, and 3) drivers’ subjective experience of the vehicle, the driving environment and the own driving performance. The results showed that there were significant differences in mean speed, blink duration, percentage road centre (gaze), radius of 95 per cent cone (gaze) and KSS between the simulator and the real road. No such differences were found for left and right line crossings. For all indicators except blink duration, there was no interaction effect between platform (simulator vs. real road) and time on task, which indicates that the signs of sleepiness vary in a similar way regardless of platform. In conclusion, differences between the simulator and the real road with respect to driving and driver behaviour as well as subjective experiences were found, mainly in terms of speed, level of sleepiness and subjective experience of the vehicle. However, the signs of sleepiness and the development of sleepiness over time are similar in the simulator and on the real road, although the level is higher in the simulator. Thus, there is a relative but not absolute validity with respect to driver sleepiness. Similarly, there seems to be a relative validity for speed and changes in speed.
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| 6. |
- Hallvig, D., et al.
(författare)
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Sleepy driving on the real road and in the simulator - A comparison
- 2013
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575 .- 1879-2057. ; 50, s. 44-50
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Tidskriftsartikel (refereegranskat)abstract
- Sleepiness has been identified as one of the most important factors contributing to road crashes. However, almost all work on the detailed changes in behavior and physiology leading up to sleep related crashes has been carried out in driving simulators. It is not clear, however, to what extent simulator results can be generalized to real driving. This study compared real driving with driving in a high fidelity, moving base, driving simulator with respect to driving performance, sleep related physiology (using electroencephalography and electrooculography) and subjective sleepiness during night and day driving for 10 participants. The real road was emulated in the simulator. The results show that the simulator was associated with higher levels of subjective and physiological sleepiness than real driving. However, both for real and simulated driving, the response to night driving appears to be rather similar for subjective sleepiness and sleep physiology. Lateral variability was more responsive to night driving in the simulator, while real driving at night involved a movement to the left in the lane and a reduction of speed, both of which effects were absent in the simulator. It was concluded that the relative validity of simulators is acceptable for many variables, but that in absolute terms simulators cause higher sleepiness levels than real driving. Thus, generalizations from simulators to real driving must be made with great caution.
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| 7. |
- Nåbo, Arne, et al.
(författare)
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Förares tankar om framtida automatiserad bilkörning : en fokusgruppstudie
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det man ofta avser med automatiserad körning är möjligheten att låta föraren överlåta en del- eller hela köruppgiften till fordonet själv. Det kan även handla om att fordonet själv ska kunna ta över kontrollen i en situation som föraren inte klarar av. Metoden diskussion i fokusgrupp har använts för att få en bred och omfångsrik beskrivning av hur förare kan resonera kring automatiserad körning. Fyra diskussioner genomfördes med totalt 28 deltagare. Deltagarna ombads att tänka i framtida (5-20 år) möjligheter. Frågeställningar som gavs var: Vad ser man framför sig? Finns det skäl att införa automatiserad körning? Vilka funktioner vill man ha? Finns det för- och nackdelar? Hur skulle man kunna tänka kring tillit/säkerhetsfrågor om man har en bil som kör av sig själv? Den första delen av diskussionen var mer generellt fokuserad på synpunkter på automatiserad körning. Sedan fick deltagarna se filmklipp som exemplifierade olika grader av automatiserad körning, och diskussionen handlade om reflektioner på dessa. Sist fick deltagarna fylla i en enkät för att fånga varje individs tankar och åsikter. Flera olika infallsvinklar belystes och ämnen i fokus var kopplat till vem automatiserad körning är till för och vem som har råd. En hel del av diskussionen handlade om säkerhet med lite olika infallsvinklar, till exempel om det medför en ökad hastighet, tekniska problem och om datasäkerhet. En oro var att framtidens förare tappar kunskap och att utbildning blir viktigt. När det gällde framtidens fordon var det inte helt självklart att det man ser framför sig är en bil som den ser ut idag. Frågor kring ansvar, lagar och förordningar diskuterades också. En lång lista med innovativa lösningar blev även utfallet från gruppernas diskussioner. När det gällde de helautomatiserade systemen så var deltagarna mer positivt inställda till system där föraren övervakar det som sker, än system där föraren kan ägna sig åt annat. Deltagarna var i allmänhet mer positivt inställda till system som finns idag, än till mer avancerade, framtida system. Generellt kunde det noteras att vissa förare ville ha automatik för de tråkiga långa körpassen (dvs. av komfortskäl), medan andra ville ha automatik för att klara av svåra körsituationer (dvs. av säkerhetsskäl). Båda dessa behov behöver sannolikt tillgodoses i framtiden.
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| 8. |
- Åkerstedt, Torbjörn, et al.
(författare)
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Having to stop driving at night because of dangerous sleepiness : awareness, physiology and behaviour
- 2013
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Ingår i: Journal of Sleep Research. - : Wiley. - 0962-1105 .- 1365-2869. ; 22:4, s. 380-388
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Tidskriftsartikel (refereegranskat)abstract
- A large number of accidents are due to the driver falling asleep at the wheel, but details of this link have not been studied on a real road. The purpose of the present study was to describe the development of sleepiness indicators, leading to the drive being terminated prematurely by the onboard expert driving instructor because of imminent danger. Eighteen individuals participated during a day drive and a night drive on a motorway (both 90 min). Eight drivers terminated (N) prematurely (after 43 min) because of sleep-related imminent danger [according to the driving instructor or their own judgement (two cases)].The results showed very high sleepiness ratings (8.5 units on the Karolinska Sleepiness Scale) immediately before termination (<7 at a similar time interval for those 10 who completed the drive). Group N also showed significantly higher levels of sleep intrusions on the electroencephalography/electro-oculography (EEG/EOG) than those who completed the drive (group C). The sleep intrusions were increased in group N during the first 40 min of the night drive. During the day drive, sleep intrusions were increased significantly in group N. The night drive showed significant increases of all sleepiness indicators compared to the day drive, but also reduced speed and driving to the left in the lane. It was concluded that 44% of drivers during late-night driving became dangerously sleepy, and that this group showed higher perceived sleepiness and more sleep intrusions in the EEG/EOG.
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