| 1. |
- Dahlman, Joakim, 1974-, et al.
(författare)
-
Could sound be used as a strategy for reducing symptoms of perceived motion sickness?
- 2008
-
Ingår i: Journal of NeuroEngineering and Rehabilitation. - : Springer Science and Business Media LLC. - 1743-0003. ; 5:35
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Working while exposed to motions, physically and psychologically affects a person. Traditionally, motion sickness symptom reduction has implied use of medication, which can lead to detrimental effects on performance. Non-pharmaceutical strategies, in turn, often require cognitive and perceptual attention. Hence, for people working in high demand environments where it is impossible to reallocate focus of attention, other strategies are called upon. The aim of the study was to investigate possible impact of a mitigation strategy on perceived motion sickness and psychophysiological responses, based on an artificial sound horizon compared with a non-positioned sound source.Method: Twenty-three healthy subjects were seated on a motion platform in an artificial sound horizon or in non-positioned sound, in random order with one week interval between the trials. Perceived motion sickness (Mal), maximum duration of exposure (ST), skin conductance, blood volume pulse, temperature, respiration rate, eye movements and heart rate were measured continuously throughout the trials.Results: Mal scores increased over time in both sound conditions, but the artificial sound horizon, applied as a mitigation strategy for perceived motion sickness, showed no significant effect on Mal scores or ST. The number of fixations increased with time in the non-positioned sound condition. Moreover, fixation time was longer in the nonpositioned sound condition compared with sound horizon, indicating that the subjects used more time to fixate and, hence, assumingly made fewer saccades.Conclusion: A subliminally presented artificial sound horizon did not significantly affect perceived motion sickness, psychophysiological variables or the time the subjects endured the motion sickness triggering stimuli. The number of fixations and fixation times increased over time in the non-positioned sound condition.
|
|
| 2. |
- Dahlman, Joakim, 1974-, et al.
(författare)
-
Performance and Autonomic Responses during Motion Sickness
- 2009
-
Ingår i: Human Factors. - : SAGE Publications. - 0018-7208 .- 1547-8181. ; 51:1, s. 56-66
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of the study was to investigate how motion sickness, triggered by an optokinetic drum, affects short term memory performance and to explore autonomic responses to perceived motion sickness. Background: Previous research has found motion sickness to decrease performance, but it is not known how short term memory in particular is affected. Method: Thirty-eight healthy participants performed a listening span test while seated in a rotating optokinetic drum. Measurements of motion sickness, performance, heart rate, skin conductance, blood volume pulse, and pupil size were performed simultaneously throughout the experiment. Results: A total of 16 participants terminated the trial due to severe nausea, while the other 22 endured the full 25 minutes. Perceived motion sickness increased over time in both groups, but less among those who endured the trial. Short term memory performance decreased towards the end for those who terminated, while it increased for the other group. Results from the measured autonomic responses were ambiguous. Conclusion: The present study concludes that performance, measured as short term memory, declines as perceived motion sickness progresses. Application: This research has potential implications for command and control personnel in risk of developing motion sickness.
|
|
| 3. |
|
|
| 4. |
- Dahlman, Joakim, 1974-
(författare)
-
Psychophysiological and Performance Aspects on Motion Sickness
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Motion sickness is not an illness, but rather a natural autonomic response to an unfamiliar or specific stimulus. The bodily responses to motion sickness are highly individual and contextually dependent, making them difficult to predict. The initial autonomic responses are similar to the ones demonstrated when under stress. When under the influence of motion sickness, motivation and ability to perform tasks or duties are limited. However, little is known about how specific cognitive functions are affected. Furthermore, standard mitigation strategies involve medications that induce fatigue or strategies that require cognitive capabilities. Both of them may result in reduced capability to perform assigned tasks or duties. Hence, there is a need for alternative mitigation strategies.The aim of the thesis was to study psychophysiological and performance aspects on motion sickness. The long-term goal is to provide strategies for mitigation and prevention of motion sickness by identifying psychophysiological responses as predictors for both wellbeing and performance. This thesis comprises four studies, in which 91 participants were exposed to two different motion sickness stimuli, either an optokinetic drum or a motion platform. Before the tests, a method for extracting fixations from eye-tracking data was developed as a prerequisite for studying fixations as a possible mitigation strategy for reducing motion sickness. During exposure to stimuli that triggers motion sickness, performance was studied by testing short-term memory and encoding and retrieval. In the final study, the effects of an artificial sound horizon were studied with respect to its potential to subconsciously function as a mitigating source.The results of the measurements of the psychophysiological responses were in accordance with previous research, confirming the ambiguity and high individuality of the responses as well as their contextual dependencies. To study fixations, a centroid mode algorithm proved to be the best way to generate fixations from eye-movement data. In the final study, the effects of the sound horizon were compared to the effects of a non-positioned sound. In the latter condition, both fixation time and the number of fixations increased over time, whereas none of them showed a significant time effect in the sound horizon condition. The fixation time slope was significantly larger in the non-positioned sound condition compared to the sound horizon condition. Number of fixations, heart rate, and skin conductance correlated positively with subjective statements that referred to motion sickness. Among participants that were susceptible to motion sickness symptoms, short-term memory performance was negatively affected. However, no effects of motion sickness on encoding and retrieval were found, regardless of susceptibility.Future studies should continue focusing on autonomic responses and psychological issues of motion sickness. Factors such as motivation, expectancies, and previous experiences play a major and yet relatively unknown role within the motion sickness phenomena.
|
|
| 5. |
|
|
| 6. |
- Albertsson, Pontus, et al.
(författare)
-
Case study: 128 injured in rollover coach crashes in Sweden - injury outcome, mechanisms and possible effects of seat belts.
- 2006
-
Ingår i: Safety Science. - : Elsevier BV. - 0925-7535 .- 1879-1042. ; 44:2, s. 87-109
-
Tidskriftsartikel (refereegranskat)abstract
- The risk for injuries in rollover coach crashes are dependent on whether the occupants are belted or not. However, the influence of the different belt systems for reducing injuries has remained unclear. Since many injuries sustained are caused by impacts with the interior, passenger interactions or ejection through a window, the advantages by proper seat belt systems are evident. In this study, representing the most common serious crash scenario for serious injury, 128 injured in rollover cases were analysed with regard to the injury outcome, mechanisms and the possible injury reduction for occupants when using a safety belt. Furthermore, the different belt systems were compared to explain their contribution to increased safety. Based on medical reports and questioning of the passengers, the injuries sustained are recorded according to the AIS classification. The next step was the identification of the injury mechanisms, using the passenger statements as well as results from numerical occupant simulations. It is important to mention that this study was purely focused on detection of the injury mechanism to avoid the reported injuries. The possibility of additional injuries due to the wearing of a belt were not taken into account. However, the analysis of the 128 injured showed a considerable increase in safety for belted occupants through limiting interior contacts, minimising passenger interaction and reducing the possibility of ejection.
|
|
| 7. |
|
|
| 8. |
- Albertsson, Pontus, et al.
(författare)
-
Is there a pattern in European bus and coach incidents? : A literature analysis with special focus on injury causation and injury mechanisms
- 2005
-
Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575 .- 1879-2057. ; 37:2, s. 225-233
-
Tidskriftsartikel (refereegranskat)abstract
- In order to identify and describe a pattern in bus and coach incident related injuries and fatalities, and to suggest possible future measures for improvement of bus and coach safety, a literature analysis was performed. The results formed a multi-faceted pattern, which briefly can be described as follows; women travelled more frequently by bus as compared to men. Injuries sustained predominantly affected women 60 years of age and older. Of all traffic fatalities in Europe, bus and coach fatalities represented 0.3-0.5%. In the OECD countries, the risk of being killed or seriously injured was found to be seven to nine times lower for bus and coach occupants as compared to those of car occupants. Despite the fact that fatalities were more frequent on rural roads, a vast majority of all bus and coach casualties occurred on urban roads and in dry weather conditions. Boarding and alighting caused about one-third of all injury cases. Collisions were a major injury-contributing factor. Buses and coaches most frequently collided with cars, but unprotected road users were hit in about one-third of all cases of a collision, the point of impact on the bus or the coach being typically frontal or side. Rollovers occurred in almost all cases of severe coach crashes. In this type of crash projection, total ejection, partial ejection, intrusion and smoke inhalation were the main injury mechanisms and among those, ejection being the most dangerous. A 2-point belt may prevent passenger ejection, but in frontal crashes when the upper abdominal parts and the head hit the seatback in front, it could, however, contribute to head and thoracic injuries. Hence, a 3-point belt provides the best restraint in rollovers and frontal crashes.
|
|
| 9. |
- Albertsson, Pontus, 1958-
(författare)
-
Occupant casualties in bus and coach traffic : injury and crash mechanisms
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The relevance of conducting this thesis is evident by the fact that bus and coach casualties have been “stubbornly stable” in Europe recent years and a need for investigating if a similar trend could be found in Sweden is therefore obvious. It was also important to add new knowledge to the bus and coach research in Sweden, since many areas were scarcely addressed. Aims: To describe bus and coach occupants’ injuries, crash and injury mechanisms generated in a traffic environment based on data from the medical sector. Additional aims were to investigate the injury reducing effect of a 3-point belt, the effect of cross-winds, and crucial factors in the emergency- and rescue response. Material and methods: Injury data analyses were based on a complete ten-year medical data set from a catchment-area with about 130,000 inhabitants. A number of crash studies with the scope in different crash phases were conducted by applying and elaborating the Haddon matrix as a framework. An additional framework, Protocol for Major Incidents was used in order to investi-gate the emergency- and rescue response to a severe coach crash. Results: Between the first and second five-year period, the incidence of injured in non-crash in-cidents was increased by 24%. In non-crash incidents, 54% were injured; 2/3 while alighting from a bus or coach. The pre-crash factor cross-wind, in addition to vehicle design, vehicle speed and road friction, was investigated in ten crashes. It was confirmed that cross-wind, in relation to vehicle speed and slippery road conditions, needs more attention. The importance of goods load-ing and passengers’ position in the bus, was indicated by the fact that a displacement of the cen-tre of mass rearwards with 10% increased the necessary coefficient of friction with, on average 45%, which in many cases corresponded to dry road conditions. Three Swedish rollover crashes were analysed with regard to the injury outcome, mechanisms and the possible injury reduction for occupants using a safety belt. A considerable increase in safety for occupants belted with 3-point belts was shown through limiting interior contacts, occupant interaction and the possibility of ejection. Crucial post-crash factors in the emergency- and rescue response showed that ordi-nary ways of working and equipment are not always useful and proper equipment for lifting a coach body is essential in the case of a rollover. Finally, the communication between the hospitals is important, and the telephone systems may be overloaded by calls from worried relatives and media. Conclusions: In non-crash events: Non-crash events constitute a majority of all bus and coach casualties with a high proportion of elderly female occupants among the MAIS 2+ injury cases. Boarding and, especially alighting causes many injuries to the lower extremities. In the pre-crash phase: Cross-winds do affect the safety of buses and coaches and requires more at-tention. Seat belt usage among bus and coach occupants has to be increased. In the crash phase: Rollover and ejection are the major causes behind serious and fatal injuries to bus and coach occupants, consequently, retentive glazing, pillars or rails need more attention. An upgrade from 2-point seat belts to 3-point seat belts yields an increase in the estimated injury re-duction from approximately 50% up to 80% for the MAIS 2+ casualties in a rollover crash. In the post-crash phase: In order to be able to lift a coach body proper equipment originated from experience and development is essential in a rescue operation of a crashed bus or coach. Fur-thermore, to improve the emergency response inside crashed coaches proper methods originated from experience need to be developed. Euro NBAP: Based on the results and conclusions generated in this thesis, a European New Bus and Coach Assessment Programme is suggested, which would provide bus and coach occupants with a assessment programme similar to the Euro NCAP.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
- Anund, Anna, et al.
(författare)
-
Smartare Säkrare Skolbuss : ett pilotförsök i Kristianstad
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Some 400,000 children go to school by school bus in Sweden every day. The most risky situation is when the child is outside the bus entering or exiting, lack of routines being the major cause. The present study utilised off-the-shelf technology, in order to create a driver support system that raises the level of routines in school transportation and facilitates communication between the drivers and the children. Two buses, driven by seven drivers were equipped with the system during 2008, comprising data for 130 children. Moreover, two bus stops were equipped with flashing lights, triggered by radio transmitters that the children wore. The evaluations of the system showed that it does raise the level of routines and allows the drivers to survey the children in order to take action in case of an emergency. The system has frequently been used in all its parts and been considered useful. Children reported feeling more secure with the system and experienced less stress as a benefit of it. The average speed of cars has significantly been reduced by the flashing bus stops. For the cost of 0.5-2 SEK per school day and child, the system could prevent fatal injuries in school transportation, generating monetary benefits on a societal level.
|
|
| 15. |
|
|
| 16. |
- Anund, Anna, et al.
(författare)
-
Är kraven på utmärkning av skolskjutsfordon utmärkta?
- 2005
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study aimed to test whether the present law about school transportation traffic sign leads to enhanced traffic safety, measured as adjustment of traffic behaviour from fellow road users. The fellow road users' behaviour on roads with 50 km/h and 70 km/h was compared in meetings with school buses at stand still in real traffic. Three different types of signing were tested: - without any sign, - with the school transportation traffic sign only, - with the school transportation traffic sign equipped with blinking lights. The fellow road users' behaviour was measured by their speed, lateral position and fixation patterns on the buses. In order to further explore the observed driver behaviour, self reported behaviour data and experiences from the study were gathered. The study was semi experimental and involved data from 24 randomly selected drivers. The study showed that the present school transportation traffic sign does not affect road user behaviour. Only when it is combined with blinking lights it affected the drivers' behaviour. On 70 km/h roads, the average speed decreased by approximately 9 km/h as an effect of the blinking lights. On 50 km/h roads the corresponding decrease was significantly lower and only found in the nearby areas of the busses. Lateral position was not affected by any of the school transportation traffic sign conditions. The blinking lights made the drivers visually, foveally aware and at the same time these fixations on the blinking lights did not prevent fixations on other important objects, such as the bus driver. The study recommended that future school transportation signs should have blinking lights, a finding also confirmed by the drivers' self reported acceptance for such a system. The sign should be in another format and with another type of icon than the present, which in turn requires more research.
|
|
| 17. |
- Björnstig, Ulf, et al.
(författare)
-
Injury events among bus and coach occupants - Non-crash injuries as important as crash injuries
- 2005
-
Ingår i: International Association of Traffic and Safety Sciences: Research. - 0386-1112. ; 29:1, s. 79-87
-
Tidskriftsartikel (refereegranskat)abstract
- A ten year complete data set from the health sector, comprising 284 injured bus and coach occupants from a well defined area, was analyzed. The annual injury incidence was 2 per 10,000 inhabitants, 3/4 were women. In non-crash incidents, 54% were injured; 2/3 while alighting from a bus or coach. In crashes, 46% were injured; 2/3 in collisions with other vehicles and 1/3 in single vehicle crashes. During October-March, 3/4 were injured. In two single vehicle mass casualty crashes in slippery road conditions, high built coaches were hit by so high cross wind forces that they were blown off the road. This crash mechanism has received little attention earlier. Of those injured in collisions with other vehicles, 78% were injured in collisions with other heavy vehicles. Slippery conditions contributed to half of the alighting injuries. The proportion of moderate or more serious injuries (MAIS 2+) was highest in single vehicle crashes (48%) and in alighting and boarding (43%) incidents, and was lowest (5%) in collisions. Every seventh injured was treated as an in-patient on average in five days. Non-crash victims consumed 57% of all in-patient days. Conclusions: The aerodynamic cross-wind factor merits more studies. Injury reducing measures against alighting injuries, addressing especially step height and slippery conditions, may have a great potential to reduce these injuries. Rear-end collisions by other heavy vehicles in urban areas, causing a high number of “whip-lash" injuries, also need to be further addressed. The newly introduced law on compulsory seat belt use in long distance coaches may have a potential to reduce single vehicle crash and some collision injuries.
|
|
| 18. |
- Björnstig, Ulf, et al.
(författare)
-
Injury events among bus and coah occupants
- 2005
-
Ingår i: IATSS research : journal of International Association of Traffic and Safety Sciences. - 0386-1112. ; 29
-
Tidskriftsartikel (refereegranskat)
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
|
|
