| 1. |
- Lützhöft, Margareta, et al.
(författare)
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Fatigue at sea : a field study in Swedish shipping
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 2. |
- Thorslund, Birgitta, 1976-, et al.
(författare)
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Cognitive workload and visual behavior in elderly drivers with hearing loss
- 2014
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Ingår i: European Transport Research Review. - : Springer Science and Business Media LLC. - 1867-0717 .- 1866-8887. ; 6:4, s. 377-385
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to examine eye tracking data and compare visual behavior in individuals with normal hearing (NH) and with moderate hearing loss (HL) during two types of driving conditions: normal driving and driving while performing a secondary task.Methods24 participants with HL and 24 with NH were exposed to normal driving and to driving with a secondary task (observation and recall of 4 visually displayed letters). Eye movement behavior was assessed during normal driving by the following performance indicators: number of glances away from the road; mean duration of glances away from the road; maximum duration of glances away from the road; and percentage of time looking at the road. During driving with the secondary task, eye movement data were assessed in terms of number of glances to the secondary task display, mean duration of glances to the secondary task display, and maximum duration of glances to the secondary task display. The secondary task performance was assessed as well, counting the number of correct letters, the number of skipped letters, and the number of correct letters ignoring order.ResultsWhile driving with the secondary task, drivers with HL looked twice as often in the rear-view mirror than during normal driving and twice as often as drivers with NH regardless of condition. During secondary task, the HL group looked away from the road more frequently but for shorter durations than the NH group. Drivers with HL had fewer correct letters and more skipped letters than drivers with NH.
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| 3. |
- Thorslund, Birgitta, 1976-
(författare)
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Effects of hearing loss on traffic safety and mobility
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this PhD thesis was to investigate traffic safety and mobility for individuals with hearing loss (HL). Three studies were conducted: 1. a questionnaire survey aimed to evaluate differences in choice of transportation that might be related to HL, 2. a driving simulator study that looked into compensatory strategies and evaluated the efficiency of a tactile signal to alert the driver, and 3. a field study to evaluate these effects in real traffic and to evaluate a navigation system with a supportive tactile signal. The effects of HL discovered in this thesis add to the knowledge and understanding of the influence of HL on traffic safety and mobility. Differences found consistently point to a generally more cautious behavior. Compensatory and coping strategies associated with HL are bound to driving complexity and appear when complexity increases. These strategies include driving at lower speeds, using a more comprehensive visual search behavior and being less engaged in distracting activities. Evaluation of a tactile signal showed that by adding a tactile modality, some driver assistance systems can also be made accessible to drivers with HL. At the same time, the systems might be more effective for all users, since the driver can be more focused on the road. Based on the results in this thesis, drivers with HL cannot be considered an increased traffic safety risk, and there should be no need for adjustments of the requirements of hearing for a license to drive a car.
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| 4. |
- Andersson, Jan, 1965-, et al.
(författare)
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Läsbarhet av vägskyltar i form av LED-skylt : färgkombination och fontstorlekens betydelse för läsbarheten
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Läsbarheten av vägskyltar har studerats och då i LED-format. Avsikten med studien var att studera effekten av färgkombination, fontstorlek och ljusbetingelser för läsbarheten av en LED-skylt. 101 studenter deltog i studien, där 32 var män och 69 var kvinnor. Deras ålder varierade mellan 18–66 år. Valet av försökspersoner påverkades av studiens syfte, det vill säga det var inte intressant att studera vare sig skillnader mellan olika kön, ålder eller synförmåga. En statistisk analys genomfördes för att studera hur läsbarhetsavstånden varierade som en effekt av färgkombination, fontstorlek och ljusförhållanden. Vidare uppmättes belysningsstyrkan vid de datainsamlingstillfällen som genomfördes. Läsbarhetsavstånden undersöktes både i dagsljus och i mörker. Resultaten av studien visar att färgkombinationen på skylten påverkar dess läsbarhet. Skyltar med vit text på blå, brun eller grön bakgrund kunde avläsas vid längre avstånd än skyltar med svart text på vit eller orange bakgrund. Fontstorleken är också av betydelse för läsbarheten och varje ökning i fontstorlek ger en signifikant skillnad i avstånd som skylten kan avläsas på där skylten med den största fontstorleken (300 mm) avläses från längst avstånd. Skyltarna avläses även vid längre avstånd i dagsljus jämfört med mörker. Läsbarheten av skylten med den minsta fontstorleken 200 millimeter ändras dock inte signifikant vid dagsljus jämfört med mörker. Dessa entydiga resultat påvisar att samtliga variabler som studerats har betydelse för läsbarheten. Det ska dock tilläggas att försöksdeltagarna stod stilla vid de tillfällen som de avläste skyltarna och hade fri sikt till skylten.
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| 5. |
- Fredin-Knutzén, Johan, et al.
(författare)
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Train drivers' work-related stress and job satisfaction
- 2023
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Ingår i: Journal of Occupational and Environmental Medicine. - : Lippincott Williams & Wilkins. - 1076-2752 .- 1536-5948. ; 65:9, s. 775-782
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This study investigated which work-related stressors are rated highest by train drivers and which are strongest correlated with consideration to change profession.Methods: In a questionnaire, a total of 251 Swedish train drivers rated 17 work-related stressors, to which extent they had considered quitting their profession, and if they had experienced a PUT (person under train) accident.Results: PUTs (when experienced) and irregular work hours are the main stressors, but the strongest predictors of consideration to change profession are those that are encountered often, and last over time (eg, irregular work hours, r = 0.61, and major organizational changes, r = 0.51).Conclusions: For effective reduction of stress and improved job satisfaction, focus should be on aspects that affect everyday life for drivers, such as better working shifts, less delays, and improved social climate.
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| 6. |
- Hjälmdahl, Magnus, et al.
(författare)
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Driver behaviour and driver experience of partial and fully automated truck platooning : a simulator study
- 2017
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Ingår i: European Transport Research Review. - : Springer Science and Business Media LLC. - 1867-0717 .- 1866-8887. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- This paper builds our knowledge of truck driver behaviour in and experience of automated truck platooning, focusing on the effect of partially and fully automated truck platoons on driver workload, trust, acceptance, performance, and sleepiness.Twenty-four male drivers experienced three conditions in a truck driving simulator, i.e., baseline, partial automation, and full automation: the baseline condition was driving with standard cruise control; partial automation was automated longitudinal control ten metres behind the truck in front, with the driver having to steer; and full automation was automated longitudinal and lateral control. Each condition was simulated in three situations: light traffic, heavy traffic, and heavy traffic plus fog.The experiment demonstrated that automation affects workload. For all workload measures, partial automation produced higher workload than did the full-automation or baseline condition. The two measures capturing trust were consistent and indicated that trust was highest under the baseline condition, with little difference between partial and full automation. Driver acceptance of both levels of automation was lower than acceptance of baseline. Drivers rated their situation awareness higher for both partial and full automation than for baseline, although both levels of automation led to higher sleepiness.The challenge when implementing truck platooning is to develop a system, including human–machine interaction (HMI), that does not overburden the driver, properly addresses driver sleepiness, and satisfies current legislation. The system also must be trusted and accepted by drivers. To achieve this, the development of well-designed HMI will be crucial.
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| 7. |
- Jansson, Jonas, 1973-, et al.
(författare)
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Driver reactions to horn and headlight warnings in critical situations : A simulator study
- 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
- This paper presents a driving simulator study on driving behavior in a critical head-on collision scenario. The study aims at providing basic understanding of driver responses to headlight and horn warning coming from another vehicle a time critical situation. In total, 48 participants drove 30 km. During the drive participants performed a secondary task, announced by a vibration in the seat. At the time of the secondary task the own vehicle was directed into the opposing lane where oncoming simulated vehicles issued a light and/or sound warnings to get the drivers attention. An additional purpose of the study was to examine if the warning coming from the other vehicle has a different effect on persons with a hearing loss. A possible application for this type of warnings is the implementation of a system for automatic activation. Systems for automatic activation of brakes and steering are currently entering the market. These systems use proximity sensors to monitor the state of surrounding road users. Depending on the specific situation the effort/possibility to avoid or mitigate an accident may differ significantly between the principle road users of a pending collision, e.g. one road user (1) may easily avoid a collision while another (2) may not be able to do so. The only possibility for the second road user (2) to avoid a collision in such a situation is to issue a warning to the first (1), so that he/she may take evasive actions. Connecting the horn and the headlight to already existing sensor system, for automatic warning activation, is a cost effective means to provide such a warning. The warnings, could of course, also be triggered manually by the driver.The results indicate that a driver who receives a warning from the oncoming vehicle responds faster to avoid the pending frontal collision. The most effective warning was the combination of horn and headlight. A majority of the participants where positive to the notion of an automated system to provide this type of warning (n=41). No significant difference in the behavior between the groups with and without hearing loss was found in this study.
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| 8. |
- Kircher, Katja, 1973-, et al.
(författare)
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Train driver attention is influenced by the type of railway signalling system
- 2022
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Ingår i: DDI 2022 Gothenburg. - Göteborg : Safer. ; , s. 50-52
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The European Rail Traffic Management System (ERTMS) will replace national standards with the aim to promote cross-border traffic and enhance efficiency. The transition involves a shift from lineside signalling to mostly in- cabin information via a Driver Machine Interface (DMI). Previous research indicates that this may lead to a decrease in driver attention to the outside world and to a decrease in workload, leading to boredom. Using a train simulator, 41 participants drove the same track with the ERTMS system and the Swedish national standard (ATC) while wearing eye- tracking equipment. Subjective workload and boredom assessments were made after each drive. An analysis of the first set of reduced data (15 participants) showed that the formal attentional requirements like the monitoring of speed changes and signals were fulfilled in almost all cases, regardless of system. Overall, however, the data indicate that in line with previous research the drivers focus their attention more to the inside of the train when using the ERTMS system. This is corroborated by the finding that horn blowing is slightly delayed with the ERTMS system. Perceived workload was generally low, with the ERTMS system experienced to be more boring. We draw the preliminary conclusion that while formal attentional requirements are fulfilled for both systems, the ERTMS system likely has a tendency to pull the drivers’ overall attention inwards. Given that for the ERTMS system most relevant information is presented inside of the train on the DMI, this is not surprising, but needs to be addressed by the authorities.
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| 9. |
- Lidestam, Björn, 1968-, et al.
(författare)
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In-Car Warnings of Emergency Vehicles Approaching: Effects on Car Drivers' Propensity to Give Way
- 2020
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Ingår i: Frontiers in Sustainable Cities. - : Frontiers Media SA. - 2624-9634. ; 2:19
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Tidskriftsartikel (refereegranskat)abstract
- Emergency driving entails substantially higher risk rates than ordinary driving, and it is crucial that other road users notice the emergency vehicles on call. Sirens and emergency lights are used to warn and demand that other road users give way and provide safe passage, but accidents still occur. The purpose of this study was to test the effect of a broadcast hyper local Emergency Vehicle Approaching (EVA) message via RDS radio, noticing that an emergency vehicle on call is approaching and demands that others give way, on the propensity of individual drivers to give way. In two simulator experiments, a total of 90 car drivers participated. In Experiment 1, drivers were passed three times by an ambulance in traffic conditions where it was easy to detect the ambulance early, and two versions of EVA message were compared to a baseline condition without a broadcast message. In Experiment 2, drivers were passed only once by an ambulance and in traffic conditions that made it difficult to detect the ambulance early, and either received an EVA message, or no message. The results showed that EVA messaging made drivers give way earlier and learned to give way earlier even without an EVA message. The main finding was that EVA messaging was necessary for making inexperienced drivers give way to an approaching emergency vehicle on call. Most of them did not know that they are obliged to give way, and some did not notice the emergency vehicle before it passed them. In conclusion, the study suggests that EVA messaging to alert and instruct drivers how to give way properly is beneficial for traffic safety and for enabling time-efficient emergency transports.
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| 10. |
- Lidestam, Björn, 1968-, et al.
(författare)
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Visual perception of speed in drivers with ADHD
- 2019
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Ingår i: International Journal of Sustainable Society. - : InderScience Publishers. - 1756-2538 .- 1756-2546. ; 11:2, s. 125-137
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Tidskriftsartikel (refereegranskat)abstract
- Effects of ADHD on driving speed were studied in a driving simulator with only visual motion cues, by comparing drivers with ADHD diagnosis (n = 36) to drivers from a normal student population (n = 28). Their task was to repeatedly accelerate to own preferred speed for a total of 26 trials (2 baseline, 24 experimental trials). Field of view (1, 3, 5, and 7 monitors) and virtual road markings (on, off) were manipulated. These eight experimental conditions were presented three times each (replicates). Overall mean speed did not differ between groups, but the ADHD group was less affected by the extra motion cues. Also, whereas the control group lowered their speed between replicates, the ADHD group did not. The combined results suggest that for ADHD drivers, speed perception is more of a rule-based skill and more based on attention, whereas the normal student population perceives speed more effortlessly.
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