Occupant Seat Position Research Articles

Injury Patterns in Vehicle Crashes: The Significance of Occupant Seating Position.

Investigating patterns among the outcomes of patients involved in motor vehicle accidents (MVAs) can provide information necessary to guide targeted interventions to improve road traffic safety. Our purpose is to identify any differences between passenger and driver injury severity and overall clinical course after MVAs. We performed a retrospective review and analysis of 3,693 patients involved in MVAs from 2016 to 2021. We divided the data into two groups, drivers and passengers, and compared the Injury Severity Score (ISS),Revised Trauma Score (RTS) on admission, days in the Intensive Care Unit (ICU), length of hospital stay (LOS), post Emergency Department (ED) disposition, discharge (DC) disposition, and signs of life on arrival (SOLA) to the ED. We compared mean ISS, New Injury Severity Score (NISS), RTS, length in ICU and LOS using a student's T-test and SOLA, post-ED and DC disposition using Chi-squareanalysis. We did not find any statistically significant difference in ISS, RTS, days in ICU, LOS, or SOLA between the drivers and passengers. However, we did find a statistically significant difference in the post-ED (X2= 113.743, p=<0.0001) and DC disposition (X2=41.172, p=<0.0001) of drivers and passengers.After the ED and DC, morepassengers were transferred to a higher level of care than expected, while the inverse was true for drivers. The number of drivers discharged to Skilled Nursing Facilities (SNFs) was also higher than expected, further contributingto the observed difference in DC disposition. Conclusion:Our study found no statistically significant difference between driver and passenger injury severity, length of hospital stay, days in ICU, and SOLA after an MVA. The clinical courses of the two groups were found to be significantly different based on post-ED and DC disposition data. We identified limitations, such as a relatively small sample size and insufficient data on specific car seat locations for passengers, underscoring the need for a more nuanced exploration. Future research must broaden its scope to encompass diverse crash scenarios, vehicle design and safety technologies, seat belt dynamics, and age- and gender-specific vulnerabilities.

Application of data-driven surrogate models for active human model response prediction and restraint system optimization

Surrogate models are a must-have in a scenario-based safety simulation framework to design optimally integrated safety systems for new mobility solutions. The objective of this study is the development of surrogate models for active human model responses under consideration of multiple sampling strategies. A Gaussian process regression is chosen for predicting injury values based on the collision scenario, the occupant's seating position after a pre-crash movement and selected restraint system parameters. The trained models are validated and assessed for each sampling method and the best-performing surrogate model is selected for restraint system parameter optimization.

Optimizing Daylight Glare and Circadian Entrainment in a Daylight-Artificial Light Integrated Scheme

Human circadian rhythm varies with different combinations of light sources. Natural light and dark patterns regulate the sleeping and waking cycles of the human body. This study aimed to develop a simplified model for daylight glare and circadian entrainment in an existing controlled daylight-artificial light integrated system. In addition, the effects of window orientation, occupant position, artificial light, daylight, and a combination of both on Circadian Stimulus (CS) were investigated. In a daylit interior space, window orientation, shading control and occupant seating position play a significant role in the CS. Simplified models to predict Daylight Glare Probability (DGP) and CS were estimated from the dataset. The developed nonlinear CS estimation models have R-squared values of 0.983 and 0.974. The precision of the models was evaluated in terms of standard error of regression (S) and AIC score. Multi-Objective Genetic Algorithm based optimization technique was developed using the above models to minimize glare and maximize CS in the working space. This optimisation methodology aids in implementing a complete automation algorithm for the test workbench to achieve visual comfort and circadian entrainment.

Use of Real-Time Traffic and Signal Timing Data in Modeling Occupant Injury Severity at Signalized Intersections

This study explored the use of real-time traffic events and signal timing data to determine the factors influencing the injury severity of vehicle occupants at intersections. The analysis was based on 3 years (2017–2019) of crash and high-resolution traffic data. The best fit regression was first identified by comparing the conventional regression model and logistic models with random effect. The logistic model with a heavy-tailed distribution random effect best fitted the data set, and it was used in the variable assessment. The model results revealed that about 13.6% of the unobserved heterogeneity comes from site-specific variations, which underlines the need to use the logistic model with a random effect. Among the real-time traffic events and signal-based variables, approach delay and platoon ratio significantly influenced the injury severity of vehicle occupants at 90% Bayesian credible interval. Additionally, the manner of a collision, occupant seat position, number of vehicles involved in a crash, gender, age, lighting condition, and day of the week significantly affected the vehicle occupant injury. The study findings are anticipated to provide valuable insights to transportation agencies for developing countermeasures to mitigate the crash severity risk proactively.

Analysis of Injury Severity involving of Passenger Vehicles’ Occupants in Frontal Impact Collisions

&#x0D; &#x0D; &#x0D; In Malaysia, Passenger Vehicles (PV) accounted for the second-highest proportion of vehicles involved in road crashes (13.5%) as well as the total number of casualties (18.6%) after motorcycles. This raised the alarm that a thorough investigation should be conducted on the injury severity of occupants in PV crashes involving frontal impact collisions. The objective of this study is to evaluate injury severity outcome based on the selected crash parameters for the front seat occupants involved in frontal impact collision. The data for this study was sourced from the MIROS crash investigation database (MICARS) from 2007 until 2019, during which MIROS had investigated a total of 975 cases in both East and West Malaysia. After filtering through the cases, a total of 129 frontal impact crashes (PV versus PV) involving 206 PV and 349 front seat occupants were selected for data analysis. From the total number of selected cases, 82 cases were involved in head-on collisions while 47 cases were involved in side-impact collisions. As a result, crash configuration, crush extent, airbag availability, and seatbelt wearing are strongly related to the level of injury severity of frontal seat occupants involved in a frontal impact collision. Meanwhile, collision types and occupant seating position do not appear to be significantly related to the severity of the occupants’ injuries.&#x0D; &#x0D; &#x0D;

An evaluation of occupant dynamics during moderate-to-high speed side impacts.

The present study examined trends in occupant dynamics during side impact testing in vehicle models over the past decade. "Moderate-to-high" speed side impacts (delta-V ≥15 km/h) were analyzed. The Insurance Institute for Highway Safety (IIHS) side impact crash data was examined (N = 126). The test procedure involved a moving deformable barrier (MDB) impacting the sides of stationary vehicles at 50.0 km/h. Instrumented 5th-percentile female SID IIs dummies were positioned in the driver and left rear passenger seats. Occupant head, neck, shoulder, torso, spine, and pelvis/femur responses (times histories, peaks, and time-to-peak values) were evaluated and compared to injury assessment reference values (IARVs). The effects of delta-V, vehicle model year, vehicle body type, and occupant seating position on dynamic responses were examined. The vehicle lateral delta-Vs ranged from 15.9 to 34.5 km/h. The MY2018-2020 demonstrated lower peak dynamics than MY2010-2013, for the driver head acceleration (53.7 ± 11.3g vs 46.4 ± 11.6g), shoulder lateral forces (1.7 ± 0.7 kN vs 1.5 ± 0.2 kN), average rib deflection (29.8 ± 8.3 mm vs 28.4 ± 6.2 mm), spine accelerations at T4 (51.4 ± 23.4g vs 39.6 ± 5.9g) and T12 (56.3 ± 18.5g vs 45.2 ± 9.6g), iliac forces (1.9 ± 1.0 kN vs 1.2 ± 0.9 kN), and acetabular forces (1.9 ± 0.8 kN vs 1.3 ± 0.5 kN). The driver indicated statistically higher dynamic responses than the left rear passenger. Higher wheelbase vehicles generally showed lower occupant loading than the smaller vehicles. In conclusion, a reduction in occupant loading and risks for injury was observed in vehicle models over the past decade. This provides further insight into injury mechanisms, occupant dynamics simulations, and seat/restraint design.

On scene injury severity prediction (OSISP) algorithm for car occupants

Many victims in traffic accidents do not receive optimal care due to the fact that the severity of their injuries is not realized early on. Triage protocols are based on physiological and anatomical criteria and subsequently on mechanisms of injury in order to reduce undertriage. In this study the value of accident characteristics for field triage is evaluated by developing an on scene injury severity prediction (OSISP) algorithm using only accident characteristics that are feasible to assess at the scene of accident. A multivariate logistic regression model is constructed to assess the probability of a car occupant being severely injured following a crash, based on the Swedish Traffic Accident Data Acquisition (STRADA) database. Accidents involving adult occupants for calendar years 2003–2013 included in both police and hospital records, with no missing data for any of the model variables, were included. The total number of subjects was 29128, who were involved in 22607 accidents. Partition between severe and non-severe injury was done using the Injury Severity Score (ISS) with two thresholds: ISS>8 and ISS>15. The model variables are: belt use, airbag deployment, posted speed limit, type of accident, location of accident, elderly occupant (>55 years old), sex and occupant seat position. The area under the receiver operator characteristic curve (AUC) is 0.78 and 0.83 for ISS>8 and ISS>15, respectively, as estimated by 10-fold cross-validation. Belt use is the strongest predictor followed by type of accident. Posted speed limit, age and accident location contribute substantially to increase model accuracy, whereas sex and airbag deployment contribute to a smaller extent and seat position is of limited value. These findings can be used to refine triage protocols used in Sweden and possibly other countries with similar traffic environments.

Numerical Methods and Applications in Biomechanical Modeling

Numerical Methods and Applications in Biomechanical Modeling

Serious head and neck injury as a predictor of occupant position in fatal rollover crashes

Serious head and neck injuries are a common finding in fatalities associated with rollover crashes. In some fatal rollover crashes, particularly when ejection occurs, the determination of which occupant was driving at the time of the crash may be uncertain. In the present investigation, we describe the analysis of rollover crash data from the National Automotive Sampling System–Crashworthiness Data System for the years 1997 through 2007 in which we examined the relationship between a serious head and neck injury in an occupant and a specified degree of roof deformation at the occupant's seating position. We found 960 occupants who qualified for the analysis, with 142 deaths among the subjects. Using a ranked composite head and neck injury score (the HNISS) we found a strong relationship between HNISS and the degree of roof crush. As a result of the analysis, we arrived at a predictive model, in which each additional unit increase in HNISS equated to an increased odds of roof crush as follows: for ≥8cm of roof crush compared with <8cm by 4%, for ≥15cm of roof crush compared to <8cm by 6% and for ≥30cm of roof crush compared to <8cm by 11%. We describe two hypothetical scenarios in which the model could be applied to the real world investigation of occupant position in a rollover crash-related fatality.

Characteristics of crashes involving injured children in side impacts

The objective of this study was to define the crash characteristics of near-side impact crashes in which children seated in the rear rows are injured. The crash characteristics included the direction of force, heading angle, horizontal impact location, vertical impact location, extent of deformation and intrusion at the child occupant's seating position. Cases from in-depth crash investigation databases of the NASS-CDS (National Automotive Sampling System-Crashworthiness Data System), CIREN (Crash Injury Research and Engineering Network) and Chalmers University of Technology were reviewed. The principal direction of force was most frequently between 60° and 75°. The heading angle of the bullet vehicle was most commonly between 61° and 90°. The bullet vehicle hit the passenger compartment of the target vehicle, particularly the rear door. Often, one or both of the adjacent pillars to the rear door were involved, most commonly the B pillar. In 11 of 16 crashes, the car sill was not engaged. Most commonly, the deformation extent was into Zone 3 or more – about 40 cm – and the intrusion at the child's seating position was in the range 20–30 cm. This review of the crashes revealed differences between the current side impact test procedures and the actual side impact crashes in which children were injured.

The Burden and Determinants of Neck Pain in Whiplash-Associated Disorders After Traffic Collisions: Results of the Bone and Joint Decade 2000–2010 Task Force on Neck Pain and Its Associated Disorders

Study Design Best evidence synthesis. Objective To undertake a best evidence synthesis on the burden and determinants of whiplash-associated disorders (WAD) after traffic collisions. Summary of Background Data Previous best evidence synthesis on WAD has noted a lack of evidence regarding incidence of and risk factors for WAD. Therefore there was a warrant of a reanalyze of this body of research. Methods A systematic search of Medline was conducted. The reviewers looked for studies on neck pain and its associated disorders published 1980–2006. Each relevant study was independently and critically reviewed by rotating pairs of reviewers. Data from studies judged to have acceptable internal validity (scientifically admissible) were abstracted into evidence tables, and provide the body of the best evidence synthesis. Results The authors found 32 scientifically admissible studies related to the burden and determinants of WAD. In the Western world, visits to emergency rooms due to WAD have increased over the past 30 years. The annual cumulative incidence of WAD differed substantially between countries. They found that occupant seat position and collision impact direction were associated with WAD in one study. Eliminating insurance payments for pain and suffering were associated with a lower incidence of WAD injury claims in one study. Younger ages and being a female were both associated with filing claims or seeking care for WAD, although the evidence is not consistent. Preliminary evidence suggested that headrests/car seats, aimed to limiting head extension during rear-end collisions had a preventive effect on reporting WAD, especially in females. Conclusion WAD after traffic collisions affects many people. Despite many years of research, the evidence regarding risk factors for WAD is sparse but seems to include personal, societal, and environmental factors. More research including, well-defined studies with accurate denominators for calculating risk, and better consideration of confounding factors, are needed.

The influence of damage distribution on serious brain injury in occupants in frontal motor vehicle crashes

In spite of improvements in motor vehicle safety systems and crashworthiness, motor vehicle crashes remain one of the leading causes of brain injury. The purpose of this study was to determine if the damage distribution across the frontal plane affected brain injury severity of occupants in frontal impacts. Occupants in “head on” frontal impacts with a Principal Direction of Force (PDOF) equal to 11, 12, or 1 o’clock who sustained serious brain injury were identified using the Crash Injury Research Engineering Network (CIREN) database. Impacts were further classified based on the damage distribution across the frontal plane as distributed, offset, and extreme offset (corner). Overall, there was no significant difference for brain injury severity (based on Glasgow Coma Scale < 9, or brain injury AIS > 2) comparing occupants in the different impact categories. For occupants in distributed frontal impacts, safety belt use was protective (odds ratio (OR) = 0.61) and intrusion at the occupant's seat position was four times more likely to result in severe (Glasgow Coma Scale (GCS) < 9) brain injury (OR = 4.35). For occupants in offset frontal impacts, again safety belt use was protective against severe brain injury (OR = 0.25). Possibly due to the small number of brain-injured occupants in corner impacts, safety belts did not significantly protect against increased brain injury severity during corner impacts. This study supports the importance of safety belt use to decrease brain injury severity for occupants in distributed and offset frontal crashes. It also illustrates how studying “real world” crashes may provide useful information on occupant injuries under impact circumstances not currently covered by crash testing.

The Burden and Determinants of Neck Pain in Whiplash-Associated Disorders After Traffic Collisions

Best evidence synthesis. To undertake a best evidence synthesis on the burden and determinants of whiplash-associated disorders (WAD) after traffic collisions. Summary of Background Data. Previous best evidence synthesis on WAD has noted a lack of evidence regarding incidence of and risk factors for WAD. Therefore there was a warrant of a reanalyze of this body of research. A systematic search of Medline was conducted. The reviewers looked for studies on neck pain and its associated disorders published 1980 –2006. Each relevant study was independently and critically reviewed by rotating pairs of reviewers. Data from studies judged to have acceptable internal validity (scientifically admissible) were abstracted into evidence tables, and provide the body of the best evidence synthesis. The authors found 32 scientifically admissible studies related to the burden and determinants of WAD. In the Western world, visits to emergency rooms due to WAD have increased over the past 30 years. The annual cumulative incidence of WAD differed substantially between countries. They found that occupant seat position and collision impact direction were associated with WAD in one study. Eliminating insurance payments for pain and suffering were associated with a lower incidence of WAD injury claims in one study. Younger ages and being a female were both associated with filing claims or seeking care for WAD, although the evidence is not consistent. Preliminary evidence suggested that headrests/car seats, aimed to limiting head extension during rear-end collisions had a preventive effect on reporting WAD, especially in females. WAD after traffic collisions affects many people. Despite many years of research, the evidence regarding risk factors for WAD is sparse but seems to include personal, societal, and environmental factors. More research including, well-defined studies with accurate denominators for calculating risk, and better consideration of confounding factors, are needed.

The Burden and Determinants of Neck Pain in Whiplash-Associated Disorders After Traffic Collisions

Best evidence synthesis. To undertake a best evidence synthesis on the burden and determinants of whiplash-associated disorders (WAD) after traffic collisions. Previous best evidence synthesis on WAD has noted a lack of evidence regarding incidence of and risk factors for WAD. Therefore there was a warrant of a reanalyze of this body of research. A systematic search of Medline was conducted. The reviewers looked for studies on neck pain and its associated disorders published 1980-2006. Each relevant study was independently and critically reviewed by rotating pairs of reviewers. Data from studies judged to have acceptable internal validity (scientifically admissible) were abstracted into evidence tables, and provide the body of the best evidence synthesis. The authors found 32 scientifically admissible studies related to the burden and determinants of WAD. In the Western world, visits to emergency rooms due to WAD have increased over the past 30 years. The annual cumulative incidence of WAD differed substantially between countries. They found that occupant seat position and collision impact direction were associated with WAD in one study. Eliminating insurance payments for pain and suffering were associated with a lower incidence of WAD injury claims in one study. Younger ages and being a female were both associated with filing claims or seeking care for WAD, although the evidence is not consistent. Preliminary evidence suggested that headrests/car seats, aimed to limiting head extension during rear-end collisions had a preventive effect on reporting WAD, especially in females. WAD after traffic collisions affects many people. Despite many years of research, the evidence regarding risk factors for WAD is sparse but seems to include personal, societal, and environmental factors. More research including, well-defined studies with accurate denominators for calculating risk, and better consideration of confounding factors, are needed.

Field Investigation of Child Restraints in Side Impact Crashes

Objective. Various test procedures have been suggested for assessing the protection afforded by child restraints (CRS) in lateral collisions. Analyses of real world crashes can be used to identify relevant characteristics of the child, restraint, collision, and injury mechanisms that should be incorporated into the design of the test procedures as well as in the design of related ATDs and injury metrics. The objective of this work is to use in-depth crash investigations of children restrained in CRS in side impacts to elucidate specific sources and mechanisms of injuries and explore the role of crash severity variables such as magnitude and location of intrusion and specific impact angle. Methods. Real world crashes involving children restrained in forward facing CRS in side impacts were analyzed from Partners for Child Passenger Safety, an on-going child specific crash surveillance system in which insurance claims are used to identify cases. In-depth crash investigations using standardized protocols were used to calculate the crash severity and determine the mechanisms and sources of the injuries sustained. Results. Cases of 32 children restrained in CRS in 30 side impact crashes were examined. Twenty-five percent sustained AIS 2+ injuries. The most common injuries sustained by children restrained in CRS in side impact crashes were to the face, head, and lower extremity. Characteristics of the crashes that appeared related to injury were intrusion that entered the child's occupant space or caused an interior part of the vehicle to enter the child's occupant space, forward component of the crash, and the rotation of the CRS, restrained by a seat belt, towards the side of the impact. Conclusions. The ability to assess the injury potential in a laboratory setting for the body regions of common injury, the head, face, and lower extremity, must be explored. Characteristics of a regulatory-based test procedure to assess injury risk should include a frontal component to the crash and intrusion into the occupant's seating position. Design enhancements of the CRS should address rotation during lateral impacts. These results provide guidance to current efforts to design and regulate these restraints for the safety of child passengers in side impacts.

Assessing the relative risk of severe injury in automotive crashes for older female occupants

A logistic regression model was used in the prediction of injury severity for individuals who are involved in a vehicular crash. The model identified females and older occupants (segmented by age 55–74, and 75 and older) as having a significantly higher risk of severe injuries in a crash. Further, interactions of older females with other factors, such as occupant seat position, crash type, and environmental factors were also shown to significantly impact the relative risk of a severe injury. This study revealed that females 75 years and older had the lowest odds of injury among all female occupants studied (OR = 1.16) while females between 55 and 74 years old have higher risk of severe injuries (OR = 1.74). All older females (55 and older) were at greater risk for head-on, side-impact and rear-end collisions. Seatbelt use reduced severe injuries for females in this age group, but not to the same extent as the rest of the population studied. Additionally, crashes in severe weather, which were less likely to result in severe injuries for the general population, increased the risk of severe injuries to females that were 55 and older. Among occupants of light trucks, sport utility vehicles and vans, older females were less likely than others to be severely injured. In this case, older females appear better off in vehicles which are larger and protect better in severe crashes. This research demonstrates that circumstances surrounding a crash greatly impact the severity of injuries sustained by older female occupants.