| 1. |
- Andersson, Marianne, 1969, et al.
(författare)
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Effect of booster seat design on children's choice of seating positions during naturalistic riding
- 2010
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Ingår i: Annals of Advances in Automotive Medicine - 54th Annual Scientific Conference; Las Vegas, USA, 17-20 October 2010. - 1943-2461. ; , s. 171-180
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Konferensbidrag (refereegranskat)abstract
- The purpose of this naturalistic study was to investigate the effect of booster seat design on the choice of children’s seating positions during naturalistic riding. Data was collected through observations of children during in-vehicle riding by means of a film camera. The children were positioned in high back boosters in the rear seat while a parent drove the car. The study included two different booster designs: one with large head and torso side supports, and one with small head side supports and no torso side supports. Six children between three and six years of age participated in the study. Each child was observed in both boosters. The duration of the seating positions that each child assumed was quantified. The design with large side head supports resulted more often in seating positions without head and shoulder contact with the booster’s back. There was shoulder-to-booster back contact during an average of 45% of riding time in the seat with the large head side supports compared to 75% in the seat with the small head supports. The children in the study were seated with the head in front of the front edge of the head side supports more than half the time, in both boosters. Laterally, the children were almost constantly positioned between the side supports of the booster in both seats. The observed seating positions probably reduce the desired protective effect by the side supports in side impact, and may increase the probability of head impact with the vehicle interior in frontal impact.
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| 2. |
- Arbogast, Kristy B, et al.
(författare)
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Child Occupant Protection: Latest Knowledge and Future Opportunities – Results of a 2015 Workshop in Gothenburg, Sweden
- 2015
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Ingår i: 13th International Conference on Protection of children in cars, December 3 – 4, Munich, Germany.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Child occupant protection research remains a critical need for industry, academia, government and safety advocacy organizations. While reductions in fatalities and serious injuries have been achieved, motor vehicle crashes remain a leading cause of death and disability for children and adolescents and as a result, represent a public health priority.To facilitate international coordination and sharing of knowledge around this topic, the fourth biennial international workshop on Child Occupant Protection was convened in September 2015, bringing together worldwide leaders in the fields of child occupant protection, biomechanics, and auto safety to critically review the state-of-knowledge in the field and identify high-priority research topics and strategize toward their implementation.Summaries of previous workshops were presented at the 2011 and 2013 Protection of Children in Cars Conferences. The following describes the recommendations that emanated from the 2015 meeting.
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| 3. |
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| 4. |
- Baker, Gretchen H., et al.
(författare)
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Comparison of Self-Selected, Holding Device, and Nominal Conditions on the Belt Fit and Posture of Children on Belt-Positioning Boosters
- 2023
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; , s. 665-689
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Konferensbidrag (refereegranskat)abstract
- Children assume a range of postures when utilising belt-positioning boosters, which may influence belt fit and have implications for dynamic performance. This study evaluates the belt fit and posture of children on boosters while assuming different postures: self-selected, holding device, and nominal. Children (n=25) were recruited (4–11 years, 103.0–146.5 cm, 17.8–33.6 kg) and evaluated on two of five randomised boosters. A 3D coordinate measurement device and an inertial measurement unit-based motion capture system quantified posture, e.g., head, torso, and pelvis positions and orientations, and belt fit, e.g., shoulder belt score, lap belt score, maximum gap size, gap length. Outcomes were compared across postural conditions and boosters using repeated-measures ANOVA. The device condition produced significantly more forward and flexed head postures compared to self-selected and nominal (by 58 mm and 15.0° on average). Variation was small in terms of belt fit and belt gap metrics between postural conditions, suggesting that belt routing features provided similar belt placement despite postural adjustment; however, greater variation is expected in naturalistic settings. This study is the first to directly evaluate the posture and belt fit of children while holding electronic devices and to investigate the influence of different postural conditions on belt fit and postural outcomes.
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| 5. |
- Baker, Gretchen, et al.
(författare)
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Kinematics and Shoulder Belt Engagement of Children on Belt-Positioning Boosters during Emergency Braking Events
- 2017
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; 2017-September:IRC-17-51
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Konferensbidrag (refereegranskat)abstract
- Emergency braking can influence children’s posture and seatbelt interaction. To better protect children in crashes preceded by emergency braking, this study a ims to quantify kinematics and seatbelt engagement during braking events . Eighteen rear‐seated children were exposed to braking events with 1 g deceleration in a passenger vehi cle, restrained by the seatbelt on a booster cushion and an integrated booster cushion. Vehicle acceleration and video data were analysed to m easure head displacement and shoulder belt position. On the booster cushion the belt was generally mid‐sho ulder and lower on the torso with a gap, while on the integrated booster cushion i t was closer to the neck and hi gher on the torso without a gap. Average forward head displacement was 160 mm on the booster cushion and 150 mm on the integrated booster cushion. Generally, the belt maintained the same position on the shoulde r throughout braking, with exceptions influenced by shifted initial positions or non‐standard motions. Braking e vents placed the head approximately 150‐190 mm forward from the initial position, influenced by booster, statu re, and initial seatbelt positioning. This reinforces the importance of maintaining mid‐shoulder or close to neck bel t positions and upright, centred postures prior to emergency braking, which may influence the likelihood of imp acting the vehicle interior and sustaining head injuries in a subsequent crash.
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| 6. |
- Baker, Gretchen, 1994, et al.
(författare)
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KINEMATICS AND SHOULDER BELT ENGAGEMENT OF CHILDREN ON BELT-POSITIONING BOOSTERS DURING EVASIVE STEERING MANEUVERS
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To increase the protection of child passengers in crashes preceded by evasive steering, understanding of how children interact with the seatbelt in such situations is essential. This study aims to quantify child kinematics and describe child-to-restraint interaction during evasive steering maneuvers. Methods: Eighteen child volunteers (aged 5-10) were seated on the rear seat of a passenger vehicle. A professional driver made repeatable sharp turns at 50 km/h. Children were restrained by the seatbelt on a booster cushion (BC) and on an integrated booster cushion (IBC). Kinematics of the nasion and upper sternum were analyzed with video tracking software and shoulder belt (SB) engagement and position were evaluated. Results: Children moved laterally inboard, and SB-to-body interaction was influenced by booster and stature. For shorter children, the SB was closer to the neck with more of the belt webbing in contact with the torso and a more curved belt paths on the IBC compared to the BC, where less of the SB was in contact with the torso and straight belt paths were observed throughout steering. Taller children generally had the SB initially mid-shoulder with more contact between the SB and torso, resulting in curved belt paths at initial and maximum displacement on both boosters. Children loaded the shoulder belt by axially rotating their torso into the SB more often on the IBC compared to BC. The SB generally stayed on the shoulder, with 89% of slip-off instances occurring for shorter children on the BC. Shorter children on the BC had the largest average inboard nasion displacement of 105 mm initially and 120 mm overall. Taller children on the BC had the lowest average inboard displacement of the nasion (85 mm initially, 100 mm overall). All children initially displaced on average between 65-75 mm inboard with their sternum and 90 mm overall. Conclusions: Initial SB position on the shoulder and torso differed with booster and stature, which influenced how children engaged with the seatbelt during steering. Children with less SB initially in contact with the torso moved laterally behind the belt, resulting in straighter SB paths and outboard motion of the SB on the shoulder (often ending far out or slipped-off). When more of the SB was initially in contact with the torso, children tended to engage the SB more, moving with the belt and causing the SB path to become more curved, resulting in less inboard head displacement and less outboard motion of the SB on the shoulder. Enhanced understanding of how evasive steering affects the kinematic response of children provides valuable data for protection of children in real world situations.
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| 7. |
- Bohman, Katarina, 1970, et al.
(författare)
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A comparison of seat belt fit and comfort experience between elderly and younger front seat passengers in cars
- 2019
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 20:sup2, s. S7-S12
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Tidskriftsartikel (refereegranskat)abstract
- Objective : The purpose was to study how occupant age affects seat belt fit and comfort by comparing older adults and younger occupants in the front seat of a passenger vehicle. Methods : An exploratory user study was performed for the front seat of a stationary large passenger vehicle in a laboratory environment, including 11 older (aged 72–81) and 11 younger (aged 25–30) participants. Each participant first entered the vehicle and buckled up in a predefined seat position. Next, they adjusted the seat to their preferred seat position and buckled up again. Anthropometric data were collected on height, weight, and waist and hip circumferences. Photographs and measurements were taken of seat/seat belt positions and posture, and structured interviews were conducted regarding comfort perceptions of the 2 tested scenarios, including previous experience and awareness of seat belt usage and discomfort experienced as passengers in cars. Results : Nonoptimal belt fit included shoulder belt on the shoulder edge or close to the neck or lap belt over the abdomen. Five of 11 older adults had nonoptimal belt fit in the predefined position, and in the preferred position 7 older adults had nonoptimal belt fit. Only one showed safety awareness and recognized the nonoptimal belt fit in the preferred position. In the younger group, 4 of 11 had nonoptimal belt fit in the predefined position and 4 in the preferred position. Two acknowledged the nonoptimal belt fit. Older adult participants with a more pronounced kyphotic posture had the upper part of the shoulder belt positioned closer to the suprasternal notch compared to younger participants. Older adults were also more likely to have the lower part of the shoulder belt higher up on the abdomen compared to younger participants. Participants with higher body mass indexes (BMIs) were more likely to have the shoulder belt higher up on the abdomen, independent of age and gender. When the shoulder belt was positioned higher up on the abdomen the upper portion of the shoulder belt was routed closer to the throat. Older adults preferred to sit higher up to achieve a better field of vision compared to younger adults. Conclusions : The change in body posture due to aging influences belt fit. Older adults seemed less aware of safety related to belt fit. Increased BMI influenced shoulder belt fit, independent of age. These findings are important when designing restraint systems to ensure safety for all occupants.
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| 8. |
- Bohman, Katarina, 1970, et al.
(författare)
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Kinematics and shoulder belt position of child rear seat passengers during vehicle maneuvers
- 2011
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Ingår i: Annals of Advances in Automotive Medicine. - 1943-2461. ; 55, s. 15-26
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Tidskriftsartikel (refereegranskat)abstract
- Head impact to the seat back has been identified as one important injury causation scenario for seat belt restrained, head-injured children and previous research highlighted vehicle maneuvers prior to impact as possible contributing factors. The aim was to quantify kinematics of child occupants during swerving maneuvers focusing on the child’s lateral movement and seat belt position relative to the child’s shoulder. A study was conducted on a closed-circuit test track with 16 children aged 4-12, restrained in the rear seat of a modern passenger vehicle. A professional driving instructor drove at 50 km/h making sharp turns in a repeatable fashion, resulting in inboard motion of the children. The children were exposed to two turns in each of two restraint systems. Shorter children were on a booster or highback booster cushion. The taller children were seated on a booster cushion or with only a lap and shoulder seat belt. Four film cameras were fixed in the vehicle monitoring the child. Vehicle data were also collected. The seat belt slipped off the shoulder in 1 of 5 turns, varying by age and restraint type. Among shorter children, the belt slipped off in a majority of turns when seated on a booster cushion while the belt remained on the shoulder when seated on the highback booster cushion. Among taller children, the shoulder belt moved far laterally on the shoulder in half of the turns. This data provides valuable knowledge on possible pre-impact postures of children as a result of vehicle swerving maneuvers for a variety of restraint systems.
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| 9. |
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| 10. |
- Brolin, Karin, 1974, et al.
(författare)
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Safety of children in cars: A review of biomechanical aspects and human body models
- 2015
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Ingår i: IATSS Research. - : Elsevier BV. - 0386-1112. ; 38:2, s. 92-102
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Forskningsöversikt (refereegranskat)abstract
- The protection of children in motor vehicle crashes has improved since the introduction of child restraint systems. However, motor vehicle crashes remain one of the top leading causes of death for children. Today, computer-aided engineering is an essential part of vehicle development and it is anticipated that safety assessments will increasingly rely on simulations. Therefore, this study presents a review of important biomechanical aspects for the safety of children in cars, including child human body models, for scenarios ranging from on-road driving, emergency maneuvers, and pre-crash events to crash loading. The review is divided into four parts: Crash safety, On-road driving for forward facing children, Numerical whole body models, and Discussion and future outlook.The first two parts provide ample references and a state-of-the-art description of important biomechanical aspects for the safety of children in cars. That children are not small adults has been known for decades and has been considered during the development of current restraints that protect the child in the crash phase. The head, neck, thorax, and pelvis are body areas where development with age changes the biomechanics and the interaction with restraint systems. The rear facing child seat distributes the crash load over a large area of the body and has proved to be a very efficient means of reducing child injuries and fatalities. Children up to age 4. years need to be seated rearward facing for optimal protection, mainly because of the proportionally large head, neck anthropometry and cartilaginous pelvis. Children aged 4 up to 12. years should use a belt positioning booster together with the vehicle seat belt to ensure good protection, as the pelvis is not fully developed and because of the smaller size of these children compared to adults. On-road driving studies have illustrated that children frequently change seated posture and may choose slouched positions that are poor for lap belt interaction if seated directly on the rear seat. Emergency maneuvers with volunteers illustrate that pre-crash loading forces forward-facing children into involuntary postures with large head displacements, having potential influence on the risk of head impact. Children, similar to adults, benefit from the safety systems offered in the vehicle. By providing child adaptability of the vehicle, such as integrated booster cushions, the child-restraint interaction can be further optimized. An example of this is the significant reduction of lap belt misuse when using integrated boosters, due to the simplified and natural positioning of the lap belt in close contact with the pelvis. The research presented in this review illustrates that there is a need for enhanced tools, such as child human body models, to take into account the requirements of children of different ages and sizes in the development of countermeasures.To study how children interact with restraints during on-road driving and during pre- and in-crash events, numerical child models implementing age-specific anthropometric features will be essential. The review of human whole body models covers multi body models (age 1.5 to 15. years) and finite element models (ages 3, 6, and 10. years). All reviewed child models are developed for crash scenarios. The only finite element models to implement age dependent anthropometry details for the spine and pelvis were a 3. year-old model and an upcoming 10. year-old model. One ongoing project is implementing active muscles response in a 6. year-old multi body model to study pre-crash scenarios. These active models are suitable for the next important step in providing the automotive industry with adequate tools for development and assessment of future restraint systems in the full sequence of events from pre- to in-crash.
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| 11. |
- Carlsson, Anna K, 1966, et al.
(författare)
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Barns Skallskador vid Olyckor i Personbil
- 2016
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Ingår i: Transportforum, January 12–13, 2016; Linköping, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 12. |
- Carlsson, Anna K, 1966, et al.
(författare)
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Review of Child Car Occupant Fatalities in Sweden During Six Decades
- 2013
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Ingår i: Proceedings: IRCOBI Conference; September 11-13; Gothenburg, Sweden. ; , s. 1-14
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Konferensbidrag (refereegranskat)abstract
- The development of fatal outcome was reviewed based on crash data including all fatally injured 0–14 year old car occupants in Sweden during 1956–2011 and put in relation to general improvements in vehicle and road safety and implementation of restraint systems.The review revealed a substantial decrease in crash‐related fatalities among 0–14 year old car occupants during the past three decades, representing a significant drop of 83% compared to the highest scores in the 1960s–70s. During 1992–2011, a total of 194 crash‐related fatalities were registered; the majority occurred on high‐speed roads. Head injury was a primary cause of death, in a total of 54% of all cases. Two fifths of the crashes involved a single car, while three fifths involved other vehicles. In total, 24% of the children were unrestrained, and 59% of those were ejected during crashes. Among the restrained children, 56% were considered to be appropriately restrained according to Swedish recommendations. Crash severity, complex crash situation, fire and drowning were factors that contributed to the fatal outcome, even though the restraint usage was considered to be optimal.
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| 13. |
- Charlton, Judith, et al.
(författare)
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Naturalistic Observation of Children in Cars: An International Partnership
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- It is well known that in the rear seat of cars, small children squirm, slide, slump, sleep, play and interact with their fellow passengers. Our previous findings from a pilot study show that children rarely remain in an optimal position for the efficient functioning of their restraint systems throughout the duration of their journey. Such behaviours may not only affect restraint effectiveness but may also have a negative influence on driver performance and distraction. Moreover, quantification of children’s position and out-of-position (OOP) status (i.e., their actual position relative to the ideal position for which the technology was designed) has important implications for design of test programs using anthropomorphic test devices (ATD) intended to mimic the human occupant. For example, understanding true pre-crash positions may lead to different design specifications of rear seat restraint systems and energy management features of the vehicle interior compared with the kinds of solutions that might arise from evaluations with an in-position ATD. This paper builds on our preliminary research findings and describes the design of the first international large-scale study of children in cars which uses innovative methods to observe and quantify the positions of child occupants in cars and identify the injury effects of OOP status and its impact on driver distraction. The study will facilitate a paradigm-shifting advance in child occupant protection – from the concept of safety technology designed to protect an ideally positioned occupant to the concept of dynamic restraint systems that maintain optimal restraint over a range of expected child positions/movements in a vehicle. Outcomes of the research will directly inform the design of future restraints for children, the development of appropriate crash test procedures that account for natural positions of child occupants, and the development of community awareness messages to improve the safety of children.
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| 14. |
- Hansson, Ida, 1986, et al.
(författare)
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Handling and comfort evaluation of extra seat belt concepts for rear seat passengers
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Pre-crash car manoeuvres may contribute to head injuries to restrained children in frontal impacts. Evasive steering manoeuvres can cause the shoulder belt to slide off the shoulder resulting in excessive forward head excursion. This can allow the head to get in contact with the seat back in front of them.The overall aim of this project was to evaluate different restraint concepts that can maintain the rear-seated occupant well restrained during evasive manoeuvres prior to frontal collisions. Two extra seat belt concepts, named CrissCross (CC) and BackPack (BP), for the rear seat of a passenger car were developed and installed in a Volvo V60. In the project aspects such as handling and comfort were studied, as well as user acceptance and attitude towards the two extra seat belt concepts. To fulfil the goals of the project three different studies were performed; the Guessability study, the Attitude study and the Comfort study. The studies were carried out with children, youths and adults as test subjects. The guessability study was a field study where 100 persons testing handling of the extra seat belt when seeing it for the first time. In the attitude study, 5 focus groups were conducted to explore the user’s attitude to and acceptance of extra seat belts. Moreover, in the comfort study 32 and 14 test subjects respectively evaluated use aspects such as comfort and user experience during one-hour and three-hour car rides respectively. Subjective data, colleted through interviews and questionnaires, were analysed. The data provided comprehensive information as well as understanding of how the user experienced the extra seat belts in a realistic usage situation and also their attitudes towards the extra seat belts and which factors that affect the acceptance of the product. Generally the test subjects showed a positive attitude towards the extra seat belts. Both children and adults appreciated the increased feeling of safety and after having tried both concepts in the comfort study 90 % (for CC) and 70 % (for BP) respectively said that they felt safer travelling with these belt concepts than without. Comfort was considered an important factor in both the attitude and the comfort study. Body shape and size affected the seat belt fit to a great extent and the fit of the extra seat belts affected the comfort experience for most test subjects, both initially and over time. Comfort together with the feeling of safety was pointed out as having greatest impact on preferred concept.In the attitude study 86 % of the participants preferred CC after having tried both concepts for a couple of minutes. After having tried the concepts for one hour each in the comfort study, 56% of the participants preferred CC. This result strongly indicates that the comfort experience of the extra seat belt changes over time. Those who liked CC best appreciated its symmetry, comfort and the feeling of safety. Some test subjects found CC unpleasant to wear because the belts tended to slip close to the neck, described as a strangling feeling. The test subjects who preferred BP thought it was simpler to handle and that it did not cause the same strangling feeling as CC did. Negative characteristics with BP were that it felt asymmetric to use and not as safe as CC. To conclude, this project provided a first evaluation on how people experience extra seat belts in the rear seat of a car, and which factors that affects attitudes towards it. The studies show that besides reliance in the safety of the product, comfort, information about benefits, launching approach and habit of using the product are important factors when it comes to gain acceptance. The project result contains much valuable knowledge that can benefit further development and introduction of new seat belt concepts in cars.
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| 15. |
- Jakobsson, Lotta, 1967, et al.
(författare)
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ASSESSMENT OF PASSENGER SAFETY IN FUTURE CARS - IDENTIFYING THE REAL-WORLD NEEDS TOWARDS SAFETY SYSTEM DEVELOPMENT
- 2023
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Ingår i: 27th ESV Conference Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Future cars will likely include further collision mitigation systems, seat positions and seating configurations compared to current cars, in addition to an increased degree of shared mobility solutions. At the same time the population is becoming older and the diversity in car passenger dimensions is growing. This calls for assessment tools and evaluation methods beyond the current standardized crash test methods. This paper summarizes the results of a Swedish research project on how to assess the protection of the heterogeneous population of passengers (i.e., nondrivers) in future car crashes, focusing on restraint interaction. With the overall purpose of further improving passenger protection, the specific aims were to achieve method developments based on the enhancement of tools (physical and virtual human substitutes) as well as to create knowledge on passenger protection needs. This comprehensive research project combined multiple competencies and international collaborations, and a large number of studies have been performed using different methods. The applied methods include real-world crash data analyses to identify scenarios and situations, crash testing and simulation, and additionally user-studies conducted in cars to evaluate sitting posture, beltfit, kinematics, comfort, experiences and attitudes. Furthermore, the project included studies on crash test dummies (ATDs) and Human Body Models (HBM). Moreover, adult morphed HBMs were developed in various sizes, ages and sexes, for investigating various protection principles. In novel studies, crash interventions strategies were applied to predicted residual crash configurations. User-studies provided evidence of self-selected passenger postures in real car settings and, thus, deviations from standardized ATD positions. The importance of body shape was highlighted in a beltfit user-study including older adults. Essential booster design parameters were identified for children in upright and reclined seat positions. Restraint principles were investigated for adults in reclined seat positions and with the seat in rearward positions, away from the frontal airbag and knee bolster, along with an evaluation of the capabilities of the assessment tools. The adult HBM morphed to various sizes, ages and sexes were validated for prediction of in-crash kinematics in different impact scenarios, and provided enhanced insights in passenger protection assessment compared to the three standardized sizes of ATDs. Simulations with PIPER6y, a child-sized HBM, emphasized the importance of vehiclebooster-user system interaction. The results from the research project provided input to safety system development, ATD/HBM design, assessment methods development, and a number of identified research challenges for future work. Specifically, there is a need to further explore car passenger interaction with the restraint system in terms of seat positions and variations in body sizes, shapes and postures. The inclusions of the heterogeneous population into more advanced tools such as HBMs are essential, acknowledging that when moving closer to “zero injuries”, the situations to address are more unique and specific. Although a large range of studies using different methods was conducted, many challenges still remain to cover the entire scope of passenger safety in future cars.
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| 16. |
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| 17. |
- Jakobsson, Lotta, 1967, et al.
(författare)
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Older Children's Sitting Postures when Riding in the Rear Seat
- 2011
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Ingår i: 2011 IRCOBI Conference, 14-16 September 2011, Krakow , Poland. ; , s. 137-148
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Konferensbidrag (refereegranskat)abstract
- An on‐road driving study comprising six children aged 8‐13 years (138‐150 cm) was conducted to increase theunderstanding of children’s natural sitting behavior during a car ride. Each child was video recorded during apre‐determined 40‐minute route in the rear seat of a modern car. The route was taken twice; once when thechild was restrained using a backless booster and once when the child used the seat belt only.The children spent most of their riding time in a sitting posture with their upper back and shoulders in contactwith the seat back, independent of using a booster or not. Slouched sitting postures were predominantly seenwhen restrained by the seat belt only, but in one case also when using the booster. The booster helped toposition the belt at mid shoulder. In the slouched sitting posture, the booster helped to guide the lap belt belowthe abdomen. Also, the booster helped to keep the children in a more stable lateral sitting posture.The study provides details on sitting behavior of children in the transition age for booster use adding valuableknowledge for future safety system improvements. It also takes into account comfort issues.
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| 18. |
- Jakobsson, Lotta, 1967, et al.
(författare)
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Rear-End Impact Assessment expanded with Pre-Impact Posture Variations
- 2021
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; 2021-September, s. 753-770
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Konferensbidrag (refereegranskat)abstract
- Present whiplash injury assessment tests, reflecting the seat performance only, provide limited insights into real-world whiplash injury protection needs. Virtual testing of braking followed by a rear-end impact, in addition to alternative initial sitting postures, were conducted to investigate if the current anthropomorphic test device can be used to cover a larger scope of the real-world context. Reconstruction of published 1.1 g braking volunteer tests showed that a BioRID FE model was capable of recreating human-like kinematics; with head and T1 kinematics just within a 1 SD corridor on the low side of the volunteer response, while vertical displacements and lap-belt forces were underpredicted. A simulation series including pre-impact braking prior to rear-end impact investigated two strategies to vary the backset, as well as pre-impact means of intervention, exemplified by pre-impact seatbelt pretensioning. Using virtual testing, the study demonstrates examples of expanding the whiplash assessment test setup, enabling inclusion of a variety of occupant sitting postures and a braking event preceding the rear-end impact, while still being feasible to execute. As a next step, a human body model capable of seamless pre-crash and crash prediction could even allow for more in-depth investigations, as well as inclusion of ranges of occupant sizes and posture setting possibilities.
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| 19. |
- Jakobsson, Lotta, 1967, et al.
(författare)
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Rear Seat Safety for Children Aged 4-12; Identifying the Real-World Needs Towards Development of Countermeasures
- 2017
-
Ingår i: Proceedings of the 25th International Technical Conference on the Enhanced Safety of Vehicles.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study summarizes a joint research project aiming to further enhance the safety of booster-seated children (aged 4-12) in the rear seat of passenger cars. The focus is real-world aspects of child safety, comprising the whole context of the vehicle and child restraints, and a variety of crash situations, including pre-crash events.Real children sit in a variety of sitting postures in cars. On-road driving studies show that children take different postures due to comfort, visibility or activities. The results from three studies 18 children in a variety of restraints, showed that for only a portion of the time, they are sitting upright with contact to the seatback, i.e. similar to the standardized crash test dummy position. When using a booster with protruding head side supports the children sit forward leaning more than without, and in a large share of the time, the head is in front of the head side supports.Approximately 40% of the crashes are preceded by evasive maneuvers. When exposing child volunteers to evasive braking they will move forward by up to 0.2m, when shoulder belt remains over the shoulder. Thirty four child volunteers were exposed to evasive braking and steering events, using different types of boosters. Depending of the size of the child and the booster used, they might slide out of the shoulder belt in steering events. In addition, existing child crash test dummies were tested and compared to the volunteer data. The volunteer data was also used to validate an active child Human Body Model, as a first step to develop a tool that can be used for evasive maneuvers.The booster is essential for the child enabling good interaction to the seatbelt. In addition, the vehicle protection systems play an important role for the child protection. Hence, for enhancing real-world safety it is essential to replicate in-vehicle situations. Unfortunately, this is not how child restraints are certified today. This study shows that child crash test dummies benefit from side airbags and advanced seatbelt technologies, and are responsive to changes in sitting postures and crash modes. In addition to the in-crash protective systems evaluated in this study, pioneering maneuver and run-off-road tests with crash test dummies were run to evaluate the effect of an electrical reversible seatbelt retractor (pre-pretensioner) to help keep the occupant in the belt during such an event.International multidisciplinary workshops were held and concluded that future advancements need to be data driven and incorporate multiple disciplines. Engineering advancements should strive towards less complex solutions and the shared responsibility between the child restraint and the vehicle was highlighted.The results from this project contribute to identification and quantification of important real-world needs, as well as evaluation and development of countermeasures. It is concluded, that from a real-world perspective, the vehicle and child restraint should be designed together targeting a range of acceptable common user positions; sitting postures preferably guided by comfort and positive means. Such designs will ensure robust function of the protection systems for these young occupants, and advance the development of countermeasures that protect children in real- world crashes, also including dynamic events prior to a crash.
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| 20. |
- Jakobsson, Lotta, 1967, et al.
(författare)
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REAR SEAT SAFETY IN FRONTAL TO SIDE IMPACTS – FOCUSING ON OCCUPANTS FROM 3YRS TO SMALL ADULTS
- 2011
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Ingår i: The 22nd ESV Conference Proceedings.
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Konferensbidrag (refereegranskat)abstract
- ABSTRACTThis study presents a broad comprehensiveresearch effort that combines expertise fromindustry and academia and uses variousmethodologies with applied research directedtowards countermeasures. The project includesreal world crash data analysis, real world drivingstudies and crash testing and simulations,aiming at enhancing the safety of forward facingchild occupants (aged 3y to small adults) in therear seat during frontal to side impacts.The real world crash data analyses of properlyrestrained children originate from European aswell as US data. Frontal and side impact crashtests are analyzed using different sizes of crashtest dummies in different sitting postures. Sideimpact parameter studies using FE-models arerun. The sitting posture and behavior of 12children are monitored while riding in the rearseat. Also, the body kinematics and belt positionduring actual braking and turning maneuvers arestudied for 16 rear seat child occupants and forvarious child dummies.Real world crash data indicates that several ofthe injured children in frontal impacts, despitebeing properly restrained, impacted the vehicleinterior structure with their head/face resulting inserious injury. This was attributed to obliquecrashes, pre-crash vehicle maneuvers or highcrash severity. Crash tests confirm theimportance of proper initial belt-fit for bestprotection. The crash tests also highlight thedifficulty in obtaining the real world kinematicsand head impact locations using existing crashtest dummies and test procedures. The sideimpact parameter studies indicate that thevehicle’s occupant protection systems, such asairbags and seat belt pretensioners, play animportant role in protecting children as well.The results from the on-road driving studiesillustrate the variation of sitting postures duringriding in the rear seat giving valuable input to theeffects of the restraint systems and to howrepresentative the standardized dummy seatingpositioning procedures are. The results from themaneuver driving studies illustrate theimportance of understanding the kinematics of achild relative to the seat belt in a real worldmaneuver situation.Real world safety of rear seat occupants,especially children, involves evaluation ofprotection beyond standard crash testingscenarios in frontal and side impact conditions.This project explores the complete context ofrear seat protection in impact situations rangingfrom front to side and directions in betweenhighlighting the importance of pre-crash postureand behavior.This research project at SAFER (Vehicle andTraffic Safety Centre at Chalmers), whereresearchers from the industry and universitiescooperate with the aim to further improve safetyfor children (from 3y) to small adults in the rearseat, speeds up the process to safetyimplementation due to the interaction betweenacademic and industrial researchers.
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| 21. |
- Makris, Melina, 1995, et al.
(författare)
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Comparison of Sitting Postures and Shoulder Belt Fit of Rear Seat Car Passengers Over Time in Stationary and Driven Scenarios
- 2023
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; , s. 690-707
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Konferensbidrag (refereegranskat)abstract
- Adult car passengers adopt a wide range of sitting postures while travelling. This user study compared a stationary and a driven scenario of 45 minutes each, and a stationary scenario over time, to investigate the potential influence study scenarios and time have on sitting postures and shoulder belt fit of rear seat passengers. A machine learning algorithm tracked head, upper sternum, and shoulder belt positions from video data of 13 participants, captured using two 3D cameras. The results showed small differences in the average head and sternum positions and position ranges when comparing the two scenarios. The average belt position was similar in both scenarios, but the shoulder belt tended to move closer to the neck in the driven scenario for participants with specific body shapes. Average belt, head and sternum positions were similar during the first three minutes, as for the total 45 minutes of the stationary scenario, but the position ranges were wider over the total 45 minutes. To conclude, a simplified short stationary test may be used to estimate the average postures and belt fit of passengers, but longer dynamic tests are needed to capture variations in posture and belt fit of passengers with specific body shapes.
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| 22. |
- Osvalder, Anna-Lisa, 1961, et al.
(författare)
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Adult’s and Children’s Attitudes towards Extra Seat Belts in the Rear Seats
- 2017
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; 2017-September:RC-17-52, s. 341-352
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Konferensbidrag (refereegranskat)abstract
- There is an increased risk of the shoulder belt slipping off in certain crash configurations, resulting in sub-optimal protection. An extra seat belt would improve the restraint system. The objective of this study was to identify children’s and adult’s attitudes toward extra seat belts added to the three-point belt in the rear seat of a passenger car. Five focus groups were conducted with 11 Swedish children (8-10 years), and 18 adults. Two concepts were studied, the Backpack with an extra belt over the inboard shoulder, and the Criss-Cross with an extra belt across the torso. The results showed that seat belt usage was not questioned. The three-point belt was experienced as very safe, and extra seat belts were considered to further increase safety. Both concepts were accepted, but Criss-Cross was preferred due to greater perceived safety and comfort. Discomfort occurred in both concepts due to chafing at the neck, extra pressure on the upper body, and reduced ability to move. In conclusion, extra seat belts were in line with children’s current attitudes toward car safety, while adults were more hesitant. Increased understanding of user attitudes provides input to future restraint system design, resulting in attractive systems with improved restraint function.
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| 23. |
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| 24. |
- Osvalder, Anna-Lisa, 1961, et al.
(författare)
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Children's and Adults' Comfort Experience of Extra Seat Belts When Riding in the Rear Seat of a Passenger Car
- 2015
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 16, s. 46-51
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Tidskriftsartikel (refereegranskat)abstract
- Objective:The objective of this study was to explore passengers' comfort experience of extra seat belts during on-road driving in the rear seat of a passenger car and to investigate how the use of extra belts affects children's and adults' attitudes to the product.Methods:Two different seat belt systems were tested, criss-cross (CC) and backpack (BP), consisting of the standard 3-point belt together with an additional 2-point belt. In total, 32 participants (15 children aged 6-10, 6 youths aged 11-15, and 11 adults aged 20-79, who differed considerably in size, shape, and proportions) traveled for one hour with each system, including city traffic and highway driving. Four video cameras monitored the test subject during the drive. Subjective data regarding emotions and perceived discomfort were collected in questionnaires every 20 min. A semistructured interview was held afterwards.Results:All participant groups accepted the new products and especially the increased feeling of safety (P
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| 25. |
- Osvalder, Anna-Lisa, 1961, et al.
(författare)
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Misuse of Booster Cushions – An Observation Study of Children’s Performance during Buckling Up
- 2008
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Ingår i: Annals of Advance in Automotive Medicine, AAAM 52nd Annual Scientific Conference; San Diego, CA; United States; 6 October 2008 through 8 October 2008. ; 52, s. 49-58
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Konferensbidrag (refereegranskat)abstract
- Booster cushions are effective tools to protect children from injuries in car crashes, but there remains a large amount of misuse. The aim of this study was to assess potential misuse of booster cushions in an observational laboratory study, and to identify whether booster cushion design, age or clothing had any effect. 130 Swedish children from the ages of 4-12 years participated. Each child buckled up on an integrated and on an aftermarket booster cushion in the rear seat. The older children also buckled up with seat belt only. Interviews, observations and body measurements were performed. Time to buckle up and amount of belt slack were registered. Photographs were taken to document misuse. Results showed that 77% failed to perform correct belt routing on the aftermarket cushion, independent of age, although they were familiar with this system. The misuse rate for the integrated cushion was only 4%. No misuse was found for seat belt only. Few children tightened the belt. The belt slack increased when wearing winter jackets. This indicates the importance of adding pretensioners to the rear seat. Sled tests with HIII&TNO 6y dummies were also performed for the most frequent misuse situations found. The main conclusion is that an integrated booster cushion has many advantages compared to an aftermarket cushion regarding both safety and comfort. It is easy and quick to handle, has few possibilities for misuse, has an intuitive design, the buckling up sequence is equal to buckling up with an ordinary seat belt, and younger children can buckle up correctly.
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| 26. |
- Osvalder, Anna-Lisa, 1961, et al.
(författare)
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Misuse of Booster Seats. A laboratory observation study on children’s performance during buckling up on an integrated booster cushion and an aftermarket booster cushion.
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Motor vehicle crashes are among the leading causes of morbidity and mortality among children in the age group of 4 to 8 years. It is of utmost importance that the child is using correct restraints when seated in the car, taking into consideration age, length and weight. Booster cushions are important and effective tools in the effort to protect young children from injuries in car crashes. Injuries to abdomen and spine are nearly completely eliminated in accidents with children seated correctly on booster cushions compared to only seat-belts. Though, despite all benefits, there still remains a high amount of non-use and misuse of booster cushions. Therefore it is a need for continuous improvement of the safety for rear seated children. Studies of integrated booster cushions in the rear seat have shown benefits compared to aftermarket booster cushions, both in increasing the use rate and minimising the problems of misuse of the belt during buckling up, as well as better protection of the children in car crashes.The purpose of this study was to create a deeper knowledge about how children in the age between 4-12 years perform when they are buckling up on booster cushions in the rear seat. Two concepts of booster cushions were included; an integrated booster cushion (IBC) and an aftermarket booster cushion (BC). In addition, buckling up with seat belt only was also studied for the older children. The aim of the study was to obtain information of potential misuse; i.e. type and frequency of misuse, belt slack, and time to buckle up. Furthermore, the aim was to identify if age of the children and wearing a winter jacket had an effect.In total, 130 children in the age of 4-12 years participated in the study. The distribution between boys and girls was equal, as well as between children wearing or not wearing a winter jacket. The children were from the region of Göteborg and surroundings, where traffic safety aspects often are highlighted, due to large car manufactures in the area. Only children with some experience from booster cushions/seats were used as test subjects. During the tests session, each child buckled up on an integrated booster cushion (IBC) and an aftermarket booster cushion. The older children (8-12 years) also buckled up with seat belt only. Interviews, observations and measurements of height, time to buckle up and amount of belt slack were made. Photographs were also taken to document belt fit.The results showed that 77% of the children failed to perform correct belt routing under when buckling up on BC. Nearly all cases were severe misuse. Although the majority of the children were familiar with an aftermarket booster cushion with guiding loops for the belt, this high misuse rate occurred. The misuse rate for IBC was only 4% (5 cases of 128 children). For seat belt only no misuse was shown. According to the traffic regulation, children shorter than 1350 mm should use additional protective equipment than the seat belt when travelling in cars, which is equal to 54% of the children included in the study. However, only 26 % stated that they used a booster cushion/seat, which is alarming from a safety point of view. To conclude; the integrated booster cushion concept has many advantages compared to an aftermarket cushion with guiding loops, both from a safety and comfort point of view. It is easy and quick to handle; has few possibilities to misuse, has an intuitive design, the buckling up sequence is equal to buckling up with the ordinary seat belt, and younger children can buckle up correctly. The majority of children 6 years and older buckle up themselves today, and travel in cars several days a week. They need a restraint system that is comfortable and intuitive in design, easy and quick to handle, to achieve a high usage rate and maximum protection during a crash. The integrated booster cushion concept fulfils most of these demands to a high extent.
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| 27. |
- Osvalder, Anna-Lisa, 1961, et al.
(författare)
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Older Children’s Sitting Postures, Behaviour and Comfort Experience during Ride – A Comparison between an Integrated Booster Cushion and a High-Back Booster
- 2013
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Ingår i: Proceedings 2013 IRCOBI Conference, 11-13 September, Gothenburg, Sweden. - 2235-3151. ; , s. 882-885
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Konferensbidrag (refereegranskat)abstract
- Sitting postures and comfort experience were analysed from six children aged 7-9 (131-145 cm) seated on an Integrated Booster Cushion (IBC) and a high-back Booster (hbB) during 1 hour on-road drives respectively. Data was collected from video recordings, questionnaires and interviews. When seated on the IBC the most frequent posture was with the entire back and shoulders against the backrest and the head upright. On the hbB, the shoulders were seldom against the backrest. The most frequent lateral sitting posture for both boosters was upright with the seat belt in contact with the neck or mid-shoulder. Moderate and extreme forward and lateral postures occurred occasionally. A positive attitude was found towards the IBC due to possibilities to move freely, the soft seat cushion and the absence of torso supports, but the short seat cushion created some inconvenience. The hbB was perceived hard, created a locked-in feeling and felt unpleasant due to movements when changing postures. The combination of objective and subjective measures provided valuable information regarding children’s sitting behaviour. It is obvious that children do not always sit as in crash tests. Their activities and perceived discomfort influenced the selection of sitting posture and seat belt positions.
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| 28. |
- Osvalder, Anna-Lisa, 1961, et al.
(författare)
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Seat Belt Fit and Comfort for Older Adult Front Seat Passengers in Cars
- 2019
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; :IRC-19-12, s. 32-43
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Konferensbidrag (refereegranskat)abstract
- An explorative user study was performed to study seat belt fit, perceived comfort and safety awareness of older adults in the front passenger seat of a large, stationary passenger car. The study included 55 participants between 65 and 80 years (32 males, 23 females). The participants buckled up in two scenarios, in a pre-defined seat position and in a self-adjusted preferred seat position. Anthropometric measures, photographs, and measurements of seat and seat belt positions were taken. Interviews were conducted regarding comfort perception and previous awareness of seat belt usage and discomfort. The results showed a change in seat belt fit due to older adults’ body compositions and increased BMI, and a limited safety awareness of non-optimal shoulder and lap belt fit. Some usually experienced discomfort in regular driving and used add-on accessories to increase sitting height and decrease sitting discomfort. These findings are important when designing restraint systems in future vehicles to ensure further improved safety for older adults.
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| 29. |
- Stockman, Isabelle, 1984, et al.
(författare)
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Kinematics and shoulder belt position of child anthropomorphic test devices during steering maneuvers.
- 2013
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 14:8, s. 797-806
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to quantify and compare the kinematics and shoulder belt position of child anthropomorphic test devices (ATDs) during emergency steering maneuvers. Furthermore, the ATDs were compared to the results from child volunteers aged 4 to 12 in the same test setup (Bohman, Stockman, et al. 2011).Methods: A driving study was conducted on a test track comprising 4 ATDs: the Q6, Q10, and Hybrid III (HIII) 6- and 10-year-old ATDs restrained in the rear seat of a passenger vehicle. The ATDs were exposed to 2 repeated steering maneuvers in each restraint system. The Q6 and HIII 6-year-old were restrained on booster cushions as well as high-back booster seats. The Q10 and HIII 10-year-old were restrained on booster cushions or restrained by 3-point seat belts directly on the seat. Lateral motion of the forehead and upper sternum was determined, as well as shoulder belt movement on shoulder and torso tilting angle.Results: All ATDs began to move approximately at the same point in time corresponding to a vehicle lateral acceleration of just below 0.2 g. In the later phase of the maneuver, Q10 had moved 26 percent less than the children when restrained by seat belt only and 35 percent less when on a booster cushion. Corresponding numbers for the HIII 10-year-old were 43 and 44 percent higher than for children. Compared to children, the Q6 had moved 34 percent less when restrained on a high-back booster seat and 31 percent less when on a booster cushion. Corresponding numbers for HIII 6-year-old were 7 and 28 percent higher than for children. Due to extensive variety of lateral displacements observed in the children, child performance range covers both ATD families for the evaluated sizes of 6- and 10-year-old ATDs.Conclusions: Compared to children, the HIII ATDs were closer with regards to mean values in the initial phase of the maneuver and the Q ATDs were closer in the end of the ramping phase of the lateral acceleration. The question regarding which ATD replicates better the behavior of children exposed to steering maneuvers still remains open. As shown in this study, it depends on the focus of the comparison and on what phase of the maneuver is of interest. This study provides valuable knowledge on how representative the current ATDs are for replicating potential precrash postures of children as a result of vehicle emergency steering maneuvers for a variety of restraint systems and ATD sizes.
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| 30. |
- Stockman, Isabelle, 1984, et al.
(författare)
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Kinematics of Child Volunteers and Child Anthropomorphic Test Devices During Emergency Braking Events in Real Car Environment
- 2013
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 14:1, s. 92-102
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to present, compare, and discuss the kinematic response of children and child anthropomorphic test devices (ATDs) during emergency braking events in different restraint configurations in a passenger vehicle.Methods: A driving study was conducted on a closed-circuit test track comprising 16 children aged 4 to 12 years old and the Q3, Hybrid III (HIII) 3-year-old, 6-year-old, and 10-year-old ATDs restrained on the right rear seat of a modern passenger vehicle. The children were exposed to one braking event in each of the 2 restraint systems and the ATDs were exposed to 2 braking events in each restraint system. All events had a deceleration of 1.0 g. Short children (stature 107–123 cm) and the Q3, HIII 3-year-old,and 6-year-old were restrained on booster cushions as well as high-back booster seats. Tall children (stature 135–150 cm) and HIII 10-year-old were restrained on booster cushions or restrained by 3-point belts directly on the car seat. Vehicle data were collected and synchronized with video data. Forward trajectories for the forehead and external auditory canal (ear) were determined as well ashead rotation and shoulder belt force.Results: A total of 40 trials were analyzed. Child volunteers had greater maximum forward displacement of the head and greater head rotation compared to the ATDs. The average maximum displacement for children ranged from 165 to 210 mm and 155 to 195 mm for the forehead and ear target, respectively. Corresponding values for the ATDs were 55 to 165 mm and 50 to 160 mm. The change in head angle was greater for short children than for tall children. Shoulder belt force was within the same range for short children when restrained on booster cushions or high-back booster seats. For tall children, the shoulder belt force was greater when restrained on booster cushions compared to being restrained by seat belts directly on the car seat.Conclusions: The forward displacement was within the same range for all children regardless of stature and restraint system. However, themaximum forward position depended on the initial seated posture and shoulder belt position on the shoulder. Differences could also be seen in the curvature of the neck and spine. Short children exhibited a greater flexion motion of the head, whereas a more upright posture at maximumforward position was exhibited by the tall children. The ATDs displayed less forward displacement compared to the children.
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| 31. |
- Stockman, Isabelle, 1984, et al.
(författare)
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Seat belt pre-pretensioner effect on child-sized dummies during run-off-road events
- 2017
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 18, s. S96-S102
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Run-off-road events occur frequently and can result in severe consequences. Several potential injury-causing mechanisms can be observed in the diverse types of run-off-road events. Real-world data show that different types of environments, such as rough terrain, ditch types, and whether multiple events occur, may be important contributing factors to occupant injury. Though countermeasures addressing front seat occupants have been presented, studies on rear seat occupant retention in situations such as run-off-road events are lacking. The aim of this study was to investigate the seat belt pre-pretensioner effect on rear-seated child-sized anthropomorphic test devices (ATDs) during 2 different types of run-off-road events.Methods: The study was carried out using 2 test setups: a rig test with a vehicle rear seat mounted on a multi-axial robot simulating a road departure event into a side ditch and an in-vehicle test setup with a Volvo XC60 entering a side ditch with a grass slope, driving inside the ditch, and returning back to the road from the ditch. Potential subsequent rollovers or impacts were not included in the test setups. Three different ATDs were used. The Q6 and Q10 were seated on an integrated booster cushion and the Hybrid III (HIII) 5th percentile female was positioned directly on the seat. The seat belt retractor was equipped with a pre-pretensioner (electrical reversible retractor) with 3 force level settings. In addition, reference tests with the pre-pretensioner inactivated were run. Kinematics and the shoulder belt position were analyzed.Results: In rig tests, the left-seated ATD was exposed to rapid inboard lateral loads relative to the vehicle. The displacement for each ATD was reduced when the pre-pretensioner was activated compared to tests when it was inactivated. Maximum inboard displacement occurred earlier in the event for all ATDs when the pre-pretensioner was activated. Shoulder belt slip-off occurred for the Q6 and Q10 in tests where the pre-pretensioner was inactivated. During in-vehicle tests, the left-seated ATD was exposed to an inboard movement when entering the road again after driving in the ditch. The maximum inboard head displacement was reduced in tests where the pre-pretensioner was activated compared to tests in which it was inactivated.Conclusions: During both test setups, the activation of the pre-pretensioner resulted in reduced lateral excursion of the Q6, Q10, and HIII 5th percentile female due to the shoulder belt remaining on the shoulder and supporting the side of the lower torso. The results provide new insights into the potential benefits of using a pre-pretensioner to reduce kinematic responses during complex run-off-road events through supporting the seat belt to remain on the shoulder. This study addresses potential countermeasures to improve real-world protection of rear-seated children, and it provides a broader perspective including the influence of precrash kinematics.
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| 32. |
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| 33. |
- Åkerberg Boda, Christian-Nils, 1989, et al.
(författare)
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Modelling how drivers respond to a bicyclist crossing their path at an intersection: How do test track and driving simulator compare?
- 2018
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 111, s. 238-250
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Tidskriftsartikel (refereegranskat)abstract
- Bicyclist fatalities are a great concern in the European Union. Most of them are due to crashes between motorized vehicles and bicyclists at unsignalised intersections. Different countermeasures are currently being developed and implemented in order to save lives. One type of countermeasure, active safety systems, requires a deep understanding of driver behaviour to be effective without being annoying. The current study provides new knowledge about driver behaviour which can inform assessment programmes for active safety systems such as Euro NCAP. This study investigated how drivers responded to bicyclists crossing their path at an intersection. The influences of car speed and cyclist speed on the driver response process were assessed for three different crossing configurations. The same experimental protocol was tested in a fixed-base driving simulator and on a test track. A virtual model of the test track was used in the driving simulator to keep the protocol as consistent as possible across testing environments. Results show that neither car speed nor bicycle speed directly influenced the response process. The crossing configuration did not directly influence the braking response process either, but it did influence the strategy chosen by the drivers to approach the intersection. The point in time when the bicycle became visible (which depended on the car speed, the bicycle speed, and the crossing configuration) and the crossing configuration alone had the largest effects on the driver response process. Dissimilarities between test-track and driving-simulator studies were found; however, there were also interesting similarities, especially in relation to the driver braking behaviour. Drivers followed the same strategy to initiate braking, independent of the test environment. On the other hand, the test environment affected participants' strategies for releasing the gas pedal and regulating deceleration. Finally, a mathematical model, based on both experiments, is proposed to characterize driver braking behaviour in response to bicyclists crossing at intersections. This model has direct implications on what variables an in-vehicle safety system should consider and how tests in evaluation programs should be designed.
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| 34. |
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| 35. |
- Östh, Jan, 1985, et al.
(författare)
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Head injury criteria assessment using head kinematics from crash tests and accident reconstructions
- 2023
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 24:1, s. 56-61
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to assess head injury criteria based on their correlation to brain strain in a Finite Element (FE) head model (the KTH Royal Institute of Technology model), by simulation of head kinematics data from frontal and side crash tests with Anthropomorphic Test Devices (ATDs), and from Human Body Model (HBM) accident reconstructions. Methods: Six Degrees of Freedom (DoF) head kinematic data was extracted from 221 crash tests, consisting of frontal impacts with the THOR-50M ATD, near-side and far-side impacts with the WorldSID-50M ATD, and from 19 FE HBM accident reconstructions. The head injury criteria HIC15, HIP, BrIC, UBrIC, DAMAGE and CIBIC were calculated, and FE head model simulations were conducted using the six DoF kinematics data. The 100th, 99th, and 95th percentile Maximum Principal Strains (MPS) of the brain were extracted and linear regression models with respect to the injury criteria were created. The injury criteria were then evaluated based on the coefficient of determination, R2, and the Normalized Root Mean Square Error (NRMSE) of each regression model. Results: For all the data sets combined and for the WorldSID far-side data, CIBIC had the best goodness of fit, with R2 of 0.76 and 0.85. For frontal impacts with THOR and the combined ATD data set, DAMAGE had highest R2, 0.83 and 0.78, respectively. Injury criteria including translational accelerations were ranked lower, and BrIC were among the three lowest ranked for most data sets evaluated. UBrIC generally ranked after DAMAGE and CIBIC with respect to the goodness of fit but had the lowest NRMSE for all data sets. Conclusions: The two mass-spring-damper brain surrogate model criteria, DAMAGE and CIBIC, were best in capturing the head model MPS response for both the THOR and WorldSID data sets. BrIC had lower correlation to the head model MPS and performed marginally better than the linear acceleration only criteria for all the data sets combined. This study supports the suitability of DAMAGE and CIBIC as brain injury criteria to be used with THOR-50M and WorldSID-50M in vehicle crash test conditions, as they outperform BrIC.
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