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Injury risk for matched front and rear seat car passengers by injury severity and crash type: An exploratory study
... However, Curtin and Langlois reported from a study of nearly 300 MVC fatalities that drivers were more likely to sustain brain injury and skull fractures compared to passengers, whereas splenic injuries were more commonly observed among front-seat passengers [4]. Studies of rear-seat versus front-seat occupants have been performed based on larger crash data sets and have shown that occupants in the rear are more likely to sustain fatal or severe injuries than those in the front seat [5,6]. However, advances in vehicle safety technologies since the mid-90 s have greatly improved safety for front row occupants, seemingly outperforming the advantages of being seated in the rear [6][7][8]. ...
... Studies of rear-seat versus front-seat occupants have been performed based on larger crash data sets and have shown that occupants in the rear are more likely to sustain fatal or severe injuries than those in the front seat [5,6]. However, advances in vehicle safety technologies since the mid-90 s have greatly improved safety for front row occupants, seemingly outperforming the advantages of being seated in the rear [6][7][8]. ...
... Earlier research suggested that the rear-seat row was safer for occupants in crashes than the front-seat row [25,26]. However, recent studies of restrained rear-seat occupants now point to a higher risk of death and severe injury than for belted front-seat occupants [5][6][7][8]. MVs from between 1997 and 2007 [7], as well as from 2007 and onwards [5] demonstrate lower protection in the rear-seat versus the front-seat, likely attributable to improvements in front-seat occupant protection (i.e., incorporation of load limiters and pre-tensioners, increased vehicle stiffness, and airbag availability) [5,8]. Compared to front-seat occupants (drivers and passengers), the rear-seat passengers have been shown to be more likely to sustain chest injuries, primarily caused by seatbelt loading [8]. ...
We performed a retrospective study of the injuries and characteristics of occupant fatalities in motor vehicle collisions in southeast Norway. The goal was to provide updated knowledge of injuries sustained in modern vehicles and detect possible differences in injury pattern between drivers and passengers. Forensic autopsy reports, police, and collision investigation reports from 2000 to 2014 were studied, data extracted and analyzed.
A total of 284 drivers, 80 front-seat passengers, and 37 rear-seat passengers were included, of which 67.3% died in front collisions, 13.7% in near-side impacts, 13.5% in rollovers and 5.5% in other/combined collisions. Overall, 80.5% died within one hour after the crash. The presence of fatal injuries to the head, neck, thorax and abdomen were observed in 63.6%, 10.7%, 61.6% and 27.4% respectively. All occupants with severe injuries to the head or neck had signs of direct impact with contact point injuries to the skin or skull. Injuries to the heart and spleen were less common in front-seat passengers compared to drivers. Seat belt abrasions were more common and lower extremity fractures less common in both front-seat and rear-seat passengers compared to drivers. Blood alcohol and/or drug concentrations suggestive of impairment were present in 30% of all occupants, with alcohol more often detected among front-seat passengers compared to drivers.
Few driver-specific and passenger-specific patterns of injury could be identified. When attempting to assess an occupant’s seating position within a vehicle, autopsy findings should be interpreted with caution and only in conjunction with documentation from the crash scene.
... In a 10-year set of crashes from Australia, Mitchell et al. (2015) utilized a matched cohort of front and rear seat occupants to identify age, model year, airbag deployment and roadways with higher speed limits as contributing to a higher likelihood of the rear seat occupant experiencing the more serious injury in the pair. ...
... The regression indicated that age difference (older in the second row) and crash severity as indicated by vehicle velocity difference (delta-V) were significant contributors to a model that provided a good fit to the data as indicated by the ROC and significant log likelihood test for the model. The finding that the chance of having the more severe injury occur in the second row seated occupant was increased as the crash delta-V increased is consistent with that of Mitchell et al. (2015) who found increased risk of serious injury in the second row associated with crashes on roads with speed limits over 70 km/h in Australia. It is also consistent with Kuppa et al. (2005) finding of higher head and neck loads and Mizuno et al. (2007) finding of higher head and chest injury probabilities in second row seated ATDs in relatively high delta-V crash tests. ...
... It also appears reasonable in light of Sahraei et al. (2014) finding of higher fatality risk in the second row in fatal crashes, which may tend to include a high proportion of severe crashes. The finding that age is a significant contributor to the event is also consistent with the findings from many earlier studies, where older occupants in general experience a higher injury risk but perhaps especially so in the back seat of modern vehicles (Bilston et al., 2010;Durbin et al., 2015;Mitchell et al., 2015). Carter et al. (2014) work suggests that occupant age is a more significant contributor to injury risk than either occupant gender or body mass index. ...
... In particular, many researchers highlight the relationships between occupant seat positions and injury severity. Although previous researchers asserted that the rear passenger seat is safer than the front passenger seat (Durbin et al., 2015;Evans & Frick, 1988;Kent et al., 2007;Mayrose & Priya, 2008;Mitchell et al., 2015;Smith & Cummings, 2004;Wang & Kockelman, 2005), the increased safety performance in the front seat position has changed over the last two decades (Bilston et al., 2010). Besides, unobserved heterogeneity might result in biased estimation of model parameters (Mannering & Bhat, 2014). ...
... Since the level of injury severity is ordinal in nature, the modeling approaches are mainly related to ordered response models such as ordered logit or probit models that are common methods to examine the correlates of crash injury severity. (Durbin et al., 2015;Evans & Frick, 1988;Kent et al., 2007;Mayrose & Priya, 2008;Mitchell et al., 2015;Wang & Kockelman, 2005) indicated that the rear passenger seat is safer than the front passenger seat in terms of injury severity and the rear middle seat is the safest one among all passenger seats by applying the traditional ordered logit or probit model. Besides, traditional logit and probit models were applied simultaneously to analyze the occupant injury severity and presented that the driver seat is the safest position in the vehicle (O'donnell & Connor, 1996). ...
Although many studies have investigated the correlations between injury severities and seat positions, few researchers explored the correlates of injury severities (e.g., seat positions) within a crash that results in multiple occupant injuries. Therefore, we examine the injury correlates within and between crashes, and study the correlations between seat positions and occupant injury severity by constructing a hierarchical ordered probit model. A total of 20,327 occupant injuries in 16,405 motor vehicle crashes in South Australia (2012 − 2016) are used. The results of this study indicate that the rear left passenger seat is associated with a 7.66% higher chance of getting injured (including moderate and severe injury), and the front left passenger seat is associated with a 2.94% higher chance of getting injured compared with the driver seat. Besides, the higher injury chances for other passenger seats including the rear right and rear middle seats are 4.97% and 4.74%, respectively, compared with the driver seat. Thus, this study offers passengers insightful suggestions about how to protect themselves by choosing the right passenger seat in a vehicle.
... Research that used linked hospitalisation and police-reported crash data for NSW was able to examine the effectiveness of bicycle helmets in reducing severe head injury in bicycle-vehicle collisions and demonstrated a reduction in head injury severity with helmet use. 10 Linked NSW hospitalisation and road crash data were also used to examine the injury severity of front-and rear-seated vehicle occupants injured in the same vehicle and was able to identify that rear-seat occupants sustained injuries of higher severity than front-seat car occupants, particularly in newer vehicles with airbags, implying that protective measures for rear-seat occupants need improvement. 11 Information from injury surveillance activities is regularly used to inform the development of injury prevention strategies and to evaluate the impact of these strategies on the population. 10,11 Information from injury surveillance activities is also used to estimate the burden of different types of injuries, describe the circumstances of injury events, and monitor temporal injury trends. ...
... 11 Information from injury surveillance activities is regularly used to inform the development of injury prevention strategies and to evaluate the impact of these strategies on the population. 10,11 Information from injury surveillance activities is also used to estimate the burden of different types of injuries, describe the circumstances of injury events, and monitor temporal injury trends. [12][13][14] The development of injury prevention strategies and evaluation of injury prevention policy relies on having good-quality and timely information available from injury surveillance activities. ...
Injury is one of the most common reasons why a child is hospitalised. Information gained from injury surveillance activities provides an estimate of the injury burden, describes injury event circumstances, can be used to monitor injury trends over time, and is used to design and evaluate injury prevention activities. This perspective article provides an overview of child injury surveillance capabilities within New South Wales (NSW), Australia, following a stocktake of population-based injury-related data collections using the Evaluation Framework for Injury Surveillance Systems.
Information about childhood injury in NSW is obtained from multiple administrative data collections that were not specifically designed to conduct injury surveillance. Obtaining good information for child injury surveillance in NSW will involve better coordination of information from agencies that record information about childhood injury. Regular reporting about childhood injury to provide a comprehensive profile of injuries of children and young people in the state should be considered, along with the provision and/or linkage of child injury information from multiple data collections. This could support the development of a suite of injury performance indicators to monitor childhood injury reduction strategies across NSW.
... Rear seat occupants had a higher severity of injury than the front seat occupants. 26 In present study, in addition to the ISS, we performed our analyses based on the LOS. It was previously reported that all three types of trauma scores have one positive effect on hospital LOS (GCS, ISS, and RTS)and Performance of ISS and NISS anatomical scoring systems is good in predicting hospital LOS and need for surgery. ...
The aim was to determine the relationship between the severity of the score and the child sitting position in the vehicle. In this retrospective cohort study, the severity score was obtained from HIS. After entering the data into STATA/SE version 14, univariate regression models were used to identify the potential confounding variables. Poisson regression estimators were applied to depict the relationship between safety devices, seating position of the child, and the severity indices. Out of 257 child occupants under 6 years, only 4.1% of the children used child seats and 7.7% used seat belts. There was a statistically significant positive relationship between ISS and middle rear seat (P = 0.026) and left rear seat (P = 0.000). A positive relationship existed between ISS and the right rear seat. Hospitalization of children sitting on the middle rear seat was longer than the others. The right rear seat was found to be the safest seat for children. The pattern of child accidents is different in the study region compared to other places. Local interventions should be implemented using evidences obtained from road traffic accidents. Thus, the governments should explore new strategies to increase the use of child seats by parents.
... Energies Within Rock Mass and the Associated Dynamic Rock Failures 5 and 10 m/s) were selected for impact testing based on the literature. It was found that the 10 m/s has much higher severity in injuries (type of injury, facet failure occurrence, vertebral translation) that increases with increasing impact velocity, i.e., with the accident severity, which agrees with other findings (Mitchell et al. 2015). ...
Catastrophic dynamic rock failure is one of the most challenging problems existing in the fields of civil tunneling and mining. It occurs in complex environments of geology, stress and excavation, and there is no one set of circumstances that is responsible for the phenomenon. However, a major contributing factor is believed to be energy storage and release. This paper studies and quantifies the energy release concept to advance the understanding and control of dynamic rock failures. The impacts of energy sources within rock masses on dynamic rock failures are assessed. The energy sources include strain and potential energy, the pressure energy of free and adsorbed gas and radiated seismic energy related to rock fracture or faulting. A new time-based coupled model is developed to estimate the ejection velocity when dynamic rock failures occur. Two burst scenarios are demonstrated using the proposed coupled model, i.e., a burst in the development heading of an unsupported face, and a ribside burst in a supported rib. The coupled model results show the superiority of bolts with a capacity for greater plastic elongation. Conveniently from the design perspective, maximum mesh tension is governed entirely by bolt capacity and mesh rupture strain. In addition, a rockburst hazard classification is proposed by examining a broad range of studies conducted in various disciplines to classify the relationship between injury severity and impact velocities. The hazard profile of dynamic rock failures caused by various mine layouts, structural domains, gas environments and geological sequences can then be estimated on the basis of the quantitative analysis.
... Both rear-end crashes and sideswipe crash indicators significantly decrease the probability of fatal injury for child passengers. Relevant studies [44,45] on child passenger safety in rear end crashes indicate as much. The probability of fatal injury decreases by 0.0095 for rear-end crashes and by 0.0083 for sideswipe crashes respectively. ...
Despite the recent decline in child deaths caused by road traffic crashes in high income countries, low-and middle-income countries (LMIC) have yet to experience a similar trend. Children are among the most vulnerable of road users accounting for 30-40 % of all road traffic deaths in LMICs, 50 % of which are vehicle occupants. Previous research suggests that children ages 0-9 are the second most vulnerable age group in Ghana with 54 % of the children being fatally injured in injury-related crashes. However, little has been done to identify the associated factors influencing injury severity outcomes for child passengers in Ghana. This study investigates the factors that are associated with the various injury severity outcomes for child vehicle occupants less than 9 years old involved in road crashes in Ghana from 2014 to 2020. Results indicate that older child passengers (aged 5-8) were associated with lower injury severities compared to younger passengers. Additionally, crashes in which the driver sustained more severe injuries resulted in a higher likelihood of the child passengers sustaining a fatal injury. Findings from this research emphasize the issue of child passenger safety and support transportation policy and decision making to reduce risks of injury for child passengers.
... Trauma kepala berat pada pengguna sepeda motor meningkatkan risiko meninggal di tempat kecelakaan akibat mekanisme trauma energi tinggi dan tidak memakai helm sehingga tidak adanya perlindungan terhadap kepala saat mengalami benturan (Leijdesdorff, Henry Alexander et al. 2012). Pengguna kendaraan roda empat atau mobil lebih rentan mengalami trauma thorax pada penumpang kursi depan dan trauma abdomen, punggung bawah, lumbar, dan pelvis pada penumpang kursi belakang (Mitchell, Bambach and Toson, 2015). Suatu penelitian menunjukkan cedera yang paling banyak ditemukan pada pejalan kaki anak-anak, selain cedera superfisial, adalah cedera kepala dan leher (34,6%), dengan cedera muskuloskeletal (22,2%). ...
Pendahuluan: Kecelakaan lalu lintas (KLL) merupakan penyebab utama cedera yang tidak disengaja, terhitung memiliki proporsi terbesar penyebab kematian akibat cedera yang tidak disengaja. Salah satu trauma yang paling banyak ditemukan pada kecelakaan lalu lintas adalah trauma kepala. Pada kecelakaan kendaraan bermotor roda dua maupun tiga, trauma kepala menyebabkan angka kematian paling banyak dan trauma yang paling sering diakibatkan. Penelitian ini mengkaji pola trauma kepala pada korban mati akibat kecelakaan lalu lintas. Metode: Penelitian ini merupakan penelitian deskriptif dengan studi observasional. Teknik pengambilan data yang digunakan adalah total sampling dengan sampel berupa seluruh kasus kecelakaan lalu lintas yang ditangani Instalasi Forensik RSUD Dr. Moewardi pada periode 2017-2022. Hasil: Didapatkan 147 kasus dengan trauma kepala dari 160 kasus kematian akibat kecelakaan lalu lintas. Bagian wajah lebih sering mengalami cedera dengan 145 kasus daripada bagian kepala yang tertutup rambut dengan 99 kasus. Laserasi merupakan jenis trauma yang paling banyak ditemukan pada kepala, pada wajah sebanyak 98 kasus an pada bagian yang tertutup rambut sebanyak 60 kasus. Kesimpulan: Trauma kepala memiliki angka kejadian yang tinggi pada korban mati kecelakaan lalu lintas, memiliki persentase 91,87%. Trauma kepala lebih banyak terjadi di bagian wajah daripada bagian kepala yang tertutup rambut. Laserasi merupakan jenis trauma kepala yang paling sering ditemukan
... Paired comparisons of fatality and injury outcomes using real-world collision data have been applied previously to compare front-seat occupants to rear-seat occupants in frontal collisions [1][2][3][4][5]. Front-to-rear occupant comparisons are not optimal for answering our question because front and rear seats do not have equivalent seat designs or safety devices, and the occupant compartments have different structures and geometries. ...
Forensic engineers and crash safety researchers sometimes use the injuries of a seatbelted occupant to infer the injury risk of an unbelted occupant in the same crash, had they instead been wearing a seatbelt. It is unclear, however, whether this inference is valid or how often two occupants in the same collision have similar injuries. Here, we sought to compare the injury outcomes between drivers and front‐seat passengers in frontal collisions using real‐world collision data. We compared the injury severity, quantified using the Abbreviated Injury Scale (AIS), of 22 injury categories between front‐seat occupants with matching seatbelt use and airbag deployment in single‐event frontal collisions recorded in the publicly available National Automotive Sampling System, Crashworthiness Data System (years 1993–2015) database to assess whether they had similar severity injuries. We analyzed the four combinations of seatbelt use and airbag deployment and all seatbelt/airbag conditions combined. In only 3 of 88 combinations of injuries and seatbelt/airbag conditions did more than 50% of occupant pairs have the same AIS score, although the related confidence intervals showed these proportions were not significantly greater than 50%. In contrast, we found 19 combinations of injuries and seatbelt/airbag conditions where one occupant was consistently injured more severely than the other. Our findings show that injury outcome is not similar for both front‐seat occupants in the same frontal collision with similar seatbelt and airbag conditions; however, one may be able to predict that one occupant would be more severely injured than their fellow occupant.
... Another study that examined the factors associated with injury risk for pairs of front-and second-row occupants in frontal crashes indicated that the likelihood of severe injury for the second-row seated occupant of the pair increased as the crash severity increased [19]. Furthermore, according to Mitchell et al. [20], rear seat passengers sustained injuries of higher severity than front seat passengers traveling in the same vehicle when traveling in newer vehicles. The odds of sustaining injuries as rear seat occupants compared with front seat occupants and the odds of sustaining severe rather than minimal injuries were both higher. ...
Recent studies suggest that advances in rear seat occupant protection are trailing while frontal crash prevention technologies have disproportionately improved front seat occupant safety. Therefore, the first objective of this study is to identify the safest seat for children by estimating injury severity by seat position using current crash data. The second objective of this study is to demonstrate that Level-2 and above (i.e., L2+) AVs will be significantly different from current vehicles regarding child injury severity, and therefore it is essential to find the safest seat for children in L2+ AVs. This study utilized data from the National Automotive Sampling System (NASS) to estimate crash injury severity by seat position in children. This study used the Injury Severity Score (ISS) as its measure of crash severity. The mean ISS for restrained children sitting in the front passenger seat was 0.494 (for model year > 2000 vehicles). The mean ISSs for second-row left and second-row right seats were 0.374 and 0.322, respectively. The second-row middle seat had 162, 98, and 71% lower mean ISSs than the front passenger, second-row left, and second-row right seats, respectively. Overall, in both restrained and unrestrained scenarios, the safest seat for a child was the second-row middle seat.
... Such safeguards may be applied using additional airbags or active seat belts. The comparison of the injuries of passengers seated in the front seats with the injuries of passengers seated in the rear seats was investigated by Mitchell et al. [35]. ...
Road safety problem is still topical, especially since the number of vehicles and the volume of traffic are increasing. It is possible to increase the safety of road users through systemic changes in many areas related to transport. The deformation of the vehicle body during an accident has an impact on the loads acting on the passengers. Vehicle body deformation depends on complex parameters, and knowledge of these parameters is essential for designing crumple zones and the accident reconstruction process. Knowledge of the mechanical parameters of the vehicle structure during deformation is also a reference to passenger injury indicators assessment. This paper reports results from the analytical approach for determining the protection level of personal vehicles. The proposed conception is based on the results from the static stiffness characteristic of the Ford Taurus, which gives the possibility of phenomenological and simple body crumple analytical description at a speed equal to 10 km/h, 40 km/h, 56 km/h and 60 km/h, which is an original part of the work. The approach enables us to describe the vehicle crash by focusing on variations of deformation in time, stiffness, vehicle collision time (duration), deceleration and dynamic crash force. Basing on the body stiffness data of the personal vehicle, the length of the deformation zone in the front of the car and the maximum values of force at the crash for a speed of 60 km/h are presented. Results obtained by the authors show that is possible to estimate the overloading level during the crash time of a vehicle based on the stiffness characteristic of the car body. The proposed methodology can be developed and the advantage of the presented procedure is an uncomplicated useful tool for solving complex problems of a vehicle crash.
... When two or more vehicles are involved in the same crash, we might expect to derive a relationship between the damage they suffer respectively and the severity of injury of the victims. Several studies report the incidence and severity of injuries when different types of vehicle are involved, including passenger vehicles and trucks [39,40] and motorbikes and non-motorbike vehicles [41], as well as the position of occupants inside the vehicle [42,43]. Dependence between the BI severity levels of those involved in the same crash can be especially relevant if we seek to predict the expected number of victims and their injury severity; for example, as a consequence of a safety policy or, more specifically, in the insurance context, when we wish to calculate provisions for the coverage of automobile claims. ...
Against a general trend of increasing driver longevity, the injuries suffered by vehicle occupants in Spanish road traffic crashes are analyzed by the level of severity of their bodily injuries (BI). Generalized linear mixed models are applied to model the proportion of non-serious, serious, and fatal victims. The dependence between vehicles involved in the same crash is captured by including random effects. The effect of driver age and vehicle age and their interaction on the proportion of injured victims is analyzed. We find a nonlinear relationship between driver age and BI severity, with young and older drivers constituting the riskiest groups. In contrast, the expected severity of the crash increases linearly up to a vehicle age of 18 and remains constant thereafter at the highest level of BI severity. No interaction between the two variables is found. These results are especially relevant for countries such as Spain with increasing driver longevity and an aging car fleet.
... T he vast majority (92%) of motor vehicle deaths occur in one of the front seats, largely due to occupancy rates [1]. Over the past several decades, advancements in occupant safety technology in the front seats, such as advanced seat belts, which include pretensioners and load limiters, and airbags, have improved safety in the front seats as compared to the rear seats [2,3,4]. Despite the relatively low percentage of adults sitting in the rear seats (16%), the overall exposure is still high, and an increase in ridesharing and/or the use of automated driving systems (ADS) could increase exposure [2]. ...
... By splitting V into the two contributions CMI and V r , Gulino et al. [30] evidence how IR for MAIS 3+ depends primarily on impact-related variables ( V r , and CMI), and secondarily on the age of the occupant; the vehicle category, on the other hand, is not an influencing variable on IR, unlike the registration year. In the vast scientific literature on the subject, studies can be found that deal with additional variables as the gender of the occupant [31,32] or the occupied row [33,34], but with ambiguous results in terms of ability of the individual variables in influencing IR. Regardless of the employed model, it is essential to introduce performance evaluation methods like the one based on CMI and V r that allow for a direct identification of V and IR values starting from the ADAS actuation degrees: for example, the EuroNCAP consumer program foresees the performance assessment of an Inter-Urban AEB based on V r [35]; however, V r represents only a contribution to impact severity, while the significant influence of eccentricity (CMI) on V and IR is neglected. ...
Introduction
Prospective and retrospective performance assessment of Advanced Driver Assistance Systems (ADASs) is fundamental to pilot future enhancements for active safety devices. In critical road scenarios between two vehicles where ADAS activation enables collision mitigation only, currently available assessment methodologies rely on the reconstruction of the impact phase consequent to the specific intervention on braking and steering: the velocity change sustained by the vehicle in the collision (ΔV) is retrieved, so that IR decrease for the vehicle occupants can be obtained by appropriate Injury Risk (IR) models. However, information regarding the ADAS performance is available only after the impact phase reconstruction and not just as when the criticality occurs in the pre-impact phase: the best braking and steering alternative cannot be immediately envisaged, since a direct correlation lacks between the braking/steering intervention and IR.
Method
This work highlights an ADAS performance assessment method based on the disaggregation of ΔV in the two pre-impact parameters closing velocity at collision (Vr) and impact eccentricity, represented by the Crash Momentum Index (CMI). Such a disaggregation leads to the determination of IR based solely on impact configuration between the vehicles, without directly considering the impact phase. The performance of diverse ADASs in terms of intervention logic are directly comparable based on the resulting impact configuration, associated with a single coordinate in the CMI-Vr plane and a sole IR value as a consequence.
Results
The CMI-Vr approach is employable for both purposes of prospective and retrospective performance assessment of ADAS devices. To illustrate the advantages of the methodology, a solution for prospective assessment based on the CMI-Vr plane is initially proposed and applied to case studies: this provides direct suggestions regarding the most appropriate interventions on braking and steering for IR minimization, fundamental in the tuning or development phase of an ADAS. A method for retrospective assessment is ultimately contextualized in the EuroNCAP “Car-to-Car Rear moving” test for an Inter-Urban Autonomous Emergency Braking system, a device implemented on a significant portion of the circulating fleet.
Conclusions
Based on the evidenced highlights, it is demonstrated that the approach provides complementary information compared to well-established performance assessment methodologies in all stages of an ADAS life cycle, by suggesting a direct physical connection in the pre-impact phase between the possible ADAS interventions and the foreseeable injury outcomes.
... In addition, Mayrose et al. [21] showed that patients in the rear row seat had less severe injuries and a high survival rate. The abovementioned findings are consistent with the results of this study, but Mitchell et al. [22] showed higher injury severity among rear-seat passengers than among frontseat passengers. The differences in existing research results seem to be due to differences in the direction of the vehicle collision, the accident mechanism, and the study design. ...
Purpose There have been increasing concerns about serious traffic accidents on highways. The purpose of this study was to analyze factors affecting traffic accidents on highways and the severity of the resulting injuries. Methods This retrospective study was conducted at a regional trauma center. We reviewed 594 patients who had been in 114 traffic accidents on highways from January 2018 to June 2020. We collected demographic data, clinical data, accident-related factors, and meteorological data (weather and temperature). Results Environmental risk factors were found to be significantly associated with the incidence of traffic accidents on highways. Injury severity and the death rate were higher in sedans than in any other type of vehicle. Tunnels were the most common location of accidents, accounting for 47 accidents (41.2%) and 269 injured patients (45.3%). The injury severity of individuals riding in the driver’s seat (front seat) was high, regardless of vehicle type. Three meteorological risk factors were found to be significantly associated with traffic accidents: rainy roads (odds ratio [OR] 2.08; 95% confidence interval [CI] 1.84–3.29; p=0.01), icy or snowy roads (OR 5.12; 95% CI 2.88–7.33; p<0.01), and foggy conditions (OR 2.94; 95% CI 2.15–4.03; p<0.05). Conclusions The injury severity of patients was affected by seat position and type of vehicle, and the frequency of accident was affected by the location. The incidence of traffic accidents was strongly influenced by meteorological conditions (rain, snow/ice, and fog).
... Analyses focused on variables' significance (only in statistical models) and regressions' predictive power demonstrated that impact severity is represented by the combination of numerous factors. Evidence exists indicating that occupant-related features such as seating position (Mitchell et al., 2015;Viano and Parenteau, 2008), gender and age (Newgard, 2008;Carter et al., 2014) play an important role in the associated injury outcome; for what regards the vehicle properties, the scientific literature is extensive and addresses category (Abdelwahab and Abdel-Aty, 2001;Khattak and Rocha, 2003;Wenzel and Ross, 2005), mass, and size (Wood and Simms, 2002). However, it is not uncommon to retrieve works highlighting a more significant influence of such factors if compared to other studies. ...
Thorough evaluations on injury risk (IR) are fundamental for guiding interventions toward the enhancement of both the road infrastructure and the active/passive safety of vehicles. Well-established estimates are currently based on IR functions modeled on post-crash variables, such as velocity change sustained by the vehicle (ΔV); thence, these analyses do not directly suggest how pre-crash conditions can be modified to allow for IR reduction. Nevertheless, ΔV can be disaggregated into two contributions which enable its a priori calculation, based only on the information available at the impact instant: the Crash Momentum Index (CMI), representing impact eccentricity at collision, and the closing velocity at collision (Vr).
By extensively employing the CMI indicator, this work assesses the overall influence of impact eccentricity and closing velocity on the risk for occupants to sustain a serious injury. As CMI synthesizes indications regarding ΔV, its use can be disjointed from the ΔV itself for the derivation of high-quality IR models. This feature distinguishes CMI from the other eccentricity indicators available at the state-of-the-art, allowing for the contribution of eccentricity on IR to be completely isolated. Because of this element of originality, special attention is given to the CMI variable throughout the present work.
Based on data extracted from the NASS/CDS database, the influence of the CMI and Vr variables on IR is specifically highlighted and analyzed from several perspectives. The feature ranking algorithm ReliefF, whose use is unprecedented in the accident analysis field, is first employed to assess importance of such impact-related variables in determining the injury outcome: if compared to vehicle-related and occupant-related variables (as category and age, respectively), the higher influence of CMI and Vr is initially highlighted. Secondly, the relevance of CMI and Vr is confirmed by fitting different predictive models: the fitted models which include the CMI predictor perform better than models which neglect the CMI, in terms of classical evaluation metrics. As a whole, considering the high predictive power of the proposed CMI-based models, this work provides valuable tools for the a priori assessment of IR.
... Sitting in the second row was found to increase the severe injury of passengers by 4.4% on average when compared to sitting in the front row. Higher severe injuries to a rear seat car passenger compared to a front seat car passenger was also found in the literature (Mitchell, Bambach, & Toson, 2015). Zhu and Srinivasan (2011) reported that back row seats are likely to get injured to the same level as front row occupants. ...
This paper investigates the significant contributing factors affecting the injury severity of car drivers, car passengers, and truck occupants from the aspects of car-truck collisions along interstate 80 (I-80) in Wyoming using a binary logit model with a Bayesian inference approach. Fixed- and random-effects models were developed to examine the effects on severe and non-severe injuries. Results showed that the random-effects model provided a better fit to the data than the fixed-effects model. Parameter estimates were sampled from the posterior distributions using No-U-Turn Hamiltonian Monte Carlo (NUT HMC) sampling method because of its efficiency over other Monte Carlo Markov Chain (MCMC) techniques. The analysis showed that occupant behavior characteristics, such as impaired driving, alcohol or illegal drugs, fatigue, and dangerous driving significantly increased the probability of injury severity. Unlit conditions, inclement weather, challenging roadway geometry, presence of junctions, downgrades, and curve sections were also likely to lead to more severe occupant injuries. The significant finding of this paper concludes that car drivers are more responsible than truck drivers contributing more severe injuries in car-truck collisions. Findings from this study are expected to help WYDOT and other related agencies take necessary actions and decide on management strategies in reducing car-truck collisions.
... Sitting in the second row was found to increase the severe injury of passengers by estimated odds of 2.2 times on average when compared to sitting in the front row. Higher severe injuries to a rear seat car passenger compared to a front seat car passenger was also reported in the literature (Mitchell et al., 2015). Wyoming has a mandatory seat belt use law for all occupants, regardless of the sitting position. ...
... 34 Meanwhile, a car seat should ensure users' safety in any accidents. 35 The application of the method mentioned to the car seat design can guide designers to meet user needs by accurately identifying user needs, promptly finding out innovative approaches to the concrete design cases. ...
This study proposes a new hybrid method that adopts the theory of inventive problem solving and the Kansei evaluation in quality function deployment processes to facilitate innovative new product design and evaluation in the early design phase. The hybrid model and method procedures consist of four stages. First, user satisfaction needs are identified based on a questionnaire of linear numeric rating scale, factor analysis, and an analytic hierarchy process, and the completeness and reliability of this identification are guaranteed by the use of Cronbach’s coefficient alpha statistic. Second, crucial design zones are identified by a correlation matrix, and analyzing the interrelationship matrix at the quality function deployment to establish critical innovation points. Third, the main tools of the theory of inventive problem solving are applied to address these critical innovation points. As such, several innovative alternatives are designed by combining the suitable inventive principles, design rulers, and crucial design zones. Finally, a general and rough set for the Kansei evaluation of the best design alternative is presented. Innovative car seat design is conducted to scientifically and efficiently verify this proposed method.
... In a 10-year set of crashes from Australia, Mitchell et al. [2] utilized a matched cohort of front and rear seat occupants to identify age, model year, airbag deployment and roadways with higher speed limits as contributing to a higher likelihood of the rear seat occupant experiencing the more serious injury in the pair. ...
In order to improve the safety of rear seat occupant in the 50km/h car frontal collision, the simulation model of the rear occupant restraint system based one car was established by crash simulation software MADYMO and verified by the crash test, studying the effect of the design parameters of the front seat and the safety belt on the various injuries of rear seat female occupant. Results show: 1) head injury criterion HIC15 and occipital stretching moment Myoc have a clear downward trend as the headrest stiffness of the front seat decreases from 70N/mm to 30N/mm, 2) HIC36, Myoc, left femur force Fleft, right femur force Fright and thorax 3ms resultant acceleration T3MS declines by 29.7%, 75.1%, 24.7%, 52.2% and 6.9% respectively as the backrest stiffness of the front seat drops from 84N/m to 36N/mm, 3) HIC36, Myoc, T3MS, Fleft and Fright fall obviously and the variation of D is negligent as the recliner rotational stiffness of the front seat backrest lessens compared to the original value, 4) HIC15, Myoc, T3MS and Fright drops by 18.6%, 24.0%, 6.2% and 11.7% respectively, D arises by 9% as the webbing friction coefficient of the safety belt rises from 0.2 to 0.8, 5) HIC36 and T3MS experience the obvious decline with the decrease of the retractor locking feature of the safety belt, 6) HIC15, Myoc, T3MS and Fright show a significant upward trend and Fleft falls obviously with the forward movement of the buckle location.
... Many authors conclude that wearing seat belts reduce injuries sustained during accidents or other road collisions [15]. ...
... To model the effects of various explanatory variables on the binary occupant injury severity outcome (i.e., KSI and slight injury), a logistic function was applied, following other studies regarding injury severities (Celik and Oktay, 2014;Wu et al., 2014;Haleem and Gan, 2015;Mitchell et al., 2015;Huang et al., 2016;Shaheed et al., 2016). Here, denote Y ijt as the injury severity level of casualty i in district j in year t: Y ijt = 1 for KSI and Y ijt = 0 for slight injury. ...
This study aimed to identify the factors affecting the crash-related severity level of injuries in taxis and quantify the associations between these factors and taxi occupant injury severity. Casualties resulting from taxi crashes from 2004 to 2013 in Hong Kong were divided into four categories: taxi drivers, taxi passengers, private car drivers and private car passengers. To avoid any biased interpretation caused by unobserved spatial and temporal effects, a Bayesian hierarchical logistic modeling approach with conditional autoregressive priors was applied, and four different model forms were tested. For taxi drivers and passengers, the model with space-time interaction was proven to most properly address the unobserved heterogeneity effects. The results indicated that time of week, number of vehicles involved, weather, point of impact and driver age were closely associated with taxi drivers' injury severity level in a crash. For taxi passengers' injury severity an additional factor, taxi service area, was influential. To investigate the differences between taxis and other traffic, similar models were established for private car drivers and passengers. The results revealed that although location in the network and driver gender significantly influenced private car drivers' injury severity, they did not influence taxi drivers' injury severity. Compared with taxi passengers, the injury severity of private car passengers was more sensitive to average speed and whether seat belts were worn. Older drivers, urban taxis and fatigued driving were identified as factors that increased taxi occupant injury severity in Hong Kong.
... However, when analyzed categorically (Ryb et al. 2011), newer vehicles were not significantly associated with reduced injury severity in rear-seated occupants. This finding is likely due to improvements in vehicle engineering that focused on the driver with fewer safety improvements specifically geared to rear-seated occupants (Durbin et al. 2015, Mitchell et al. 2015. ...
Background
Most studies of rear-seated occupants have focused on or included pediatric occupants which may not translate to adults. This study examines passenger, driver, vehicle and crash characteristics for rear-seated adult occupants involved in side crashes.
Methods
The National Automotive Sampling System General Estimates System (NASS/GES) for calendar years 2011–2014 was used with accompanying weights to examine the occupant, vehicle and crash characteristics associated with injury in rear-seated adults (n = 395,504) involved in a side crash. A weighted subpopulation analysis includes occupants travelling in a vehicle with an IIHS safety rating (n = 39,208), which was used to control for vehicle safety. Statistical analysis used Chi-square tests and multilevel multivariable logistic regression. Unadjusted and adjusted odds ratios (ORs) are reported with 95 % confidence intervals (95 % CIs).
Results
Rear-seated occupants on the same side as the crash impact were more likely to be severely/fatally injured than occupants seated on the opposite side (Multivariable adjusted OR: 2.54, 95 % CI: 2.31–2.79), as were those in angle crashes (Multivariable adjusted OR: 10.85, 95 % CI: 9.24–12.73). Rear-seated occupants of belted drivers were 3.28 times more likely to be belted compared to rear-seated occupants of an unbelted driver. In a subpopulation analysis of all same-side crashes, unrestrained occupants were 5.96 times more likely to be severely/fatally injured compared to restrained occupants.
Conclusion
Restraint use was protective for rear-seated adult occupants involved in side crashes, including those in same-side crashes. Angle and same-side crashes are associated with increased injury severity.
... Type of crash also has significant impact on the severity of MVC-related injury (Mitchell et al., 2015;Mohammadzadeh et al., 2015); therefore, we included it as a confounding factor in the study. However, due to the lack of more detailed information about crash conditions, such as vehicle intrusion, degree of car roll-over, and velocity of crash impact, the type of crash was stratified simply by whether a single vehicle or multiple vehicles were involved. ...
Objective:
Seatbelt use is the single most effective way to save lives in motor vehicle crashes (MVC). However, although safety belt laws have been enacted in many countries, seatbelt usage throughout the world remains below optimal levels, and educational interventions may be needed to further increase seatbelt use. In addition to reducing crash-related injuries and deaths, reduced medical expenditures resulting from seatbelt use are an additional benefit that could make such interventions cost-effective. Accordingly, the objective of this study was to estimate the correlation between seatbelt use and hospital costs of injuries involved in MVC.
Methods:
The data used in this study were from the Nebraska CODES database for motor vehicle crashes that occurred between 2004 and 2013. The hospital cost information and information about other factors were obtained by linking crash reports with hospital discharge data. A multivariable regression model was performed for the association between seatbelt use and hospital costs.
Results:
Mean hospital costs were significantly lower among motor vehicle occupants using a lap-shoulder seatbelt (2289), children's seatbelt (1473) when compared with those not using any type of seatbelt ($7099). After adjusting for relevant factors, there were still significantly decreased hospital costs for motor vehicle occupants using a lap-shoulder seatbelt (84.7%), lap-only seatbelt (74.1%), shoulder-only seatbelt (40.6%), children's seatbelt (95.9%), or booster (82.8%) compared to those not using a seatbelt.
Conclusion:
Seatbelt use is significantly associated with reduced hospital costs among injured MVC occupants. The findings in this study will provide important educational information for emergency department nurses who can encourage safety belt use for vehicle occupants.
... Accident characteristics and driver's several violations were found to be potential risk factors affecting injury severity levels. Many earlier research (Chu, 2015;Chung et al., 2014;Hao and Daniel, 2014;Kim et al., 2008;Kröyer, 2015;Ma et al., 2015;Mitchell et al., 2015;Sasidharan et al., 2015) exhibited driver's violation of speed limits were extensively associated with increasing more severe injuries. The results of another earlier research revealed that speed control might have a significant impact on decreasing more severe injuries. ...
Road traffic injuries are estimated to be one of the major causes of death worldwide and a majority of them occur in low- and middle income countries. In that respect, further studies that address to determine risk factors that may influence road traffic injury severities in the corresponding countries may contribute the existing road safety literature. This paper determines possible risk factors influencing road traffic injury severity in north-eastern Turkey. For this purpose, a retrospective cross-sectional study is conducted analysing 11,771 traffic accidents reported by the police during the sample period of 2008-2013. As the accident severity is inherently ordered, the data are analysed using both ordered and unordered response models. The estimation results reveal that several driver (age and education level), accident (speeding violation, avoiding manoeuvre and right-of-way rule), vehicle (bus/minivan, single-unit truck/heavy truck, private and single vehicles), temporal (time of day, morning peak, evening peak), environmental (summer and cloudy or rainy weather), geometry (asphalt road and road class type), and control characteristics (presence of crosswalk and traffic lights) were found to have an impact on injury severity. This paper is most probably the first attempt to analyse possible risk factors of road traffic injury severities in Turkey using both ordered and unordered response models. The evidence of this study may be valuable for future road safety policies in emerging countries.
The mandated and prevalent use of front seat belts in 4 wheeler vehicles contrasts with the disregard for the rear seat belt usage. This case series of four instances of severe hyperextension injuries in rear seat unrestrained passengers having met with a low velocity head on collision, highlights the significant morbidity associated with the latter. While other injuries sustained by unrestrained passengers in the rear seat have been highlighted in literature, there is a paucity of data in regard to peripheral vascular injuries. Each case had a similar biomechanical presentation– that of hyperextended knee injury below the front seat of the car (as the unrestrained rear seat passenger slid below and ahead post collision) giving rise to traumatic popliteal artery thrombosis and rupture at the fixed P3 (Popliteal artery third segment) segment of the popliteal artery. Despite the timely presentation and avoidance of amputation, the similar history of unrestrained passengers the similar presentation of injury in each case led to the recognition of the major preventable factor: Rear seat belts restraint. The poor enforcement of the prevalent law in the country in this respect in alignment of laws all over the world, questions the disregard with respect to rear seat belt usage at an individual level. This article hopes to bring about the awareness of the potential public health impacts of such injuries and the possible prevention of the same.
Vehicle occupancy (the number of persons per vehicle) is fundamental to evaluations of transportation system performance focused on the movement of people rather than solely vehicles. Historically, obtaining detailed estimates of occupancy has required manual (expensive) field data collection. This paper reports on a crash-based approach for estimating occupancy. Because some characteristics, such as the presence of multiple passengers aged 16 to 21, may affect the likelihood of crash involvement, the study examined ways to control possible crash bias using two methods. The first—heuristic bias correction, which entails synthesizing missing samples—is useful for smaller jurisdictions where there is no ground truth value readily available but an area-wide occupancy measure is needed. The second—statistical bias correction, which uses manual observations for calibration followed by the creation of a model—is suitable for obtaining occupancy at the corridor level. The approach is demonstrated with 12 years of fall and spring crash data for the Hampton Roads region of southeastern Virginia, U.S., representing 1.7 million people and 50,000 crashes. Testing showed estimated occupancies were within roughly 0.05 of true occupancy when corridor-specific calibration was performed. Further, the larger number of samples used for an area-wide occupancy means that heuristic bias correction is not always necessary: for cities with more than 200 samples, the difference between uncorrected and corrected occupancies was 0.02. For states that report the number of occupants for crashes with and without injury, this approach holds promise for estimating vehicle occupancy for both corridors and regions.
Children involved in car crashes can experience either direct trauma or inertial injuries resulting from interactions with external objects, such as other vehicles, or with the restraint system. Furthermore, improper use of restraint systems can lead to additional severe injuries. Recent reports from international institutions underscored the persistent prevalence of inadequate restraint systems utilization and this widespread issue increases children’s vulnerability and risk of injuries.
The aim of this study is to provide a systematic review of the literature on injuries sustained in children involved in road accidents describing and analyzing elements useful for forensic assessment.
The literature search was performed using PubMed, Scopus and Web of Science from January 1970 to March 2023. Eligible studies have investigated issues of interest to forensic medicine about traffic accidents involving pediatric passengers. A total of 69 studies satisfied the inclusion criteria and were categorized and analyzed according to the anatomical regions of the body affected (head, neck, thoraco-abdominal, and limb injuries), and the assessment of lesions in reconstruction of the accident was examined and discussed.
The review highlights that in motor vehicle accidents involving children, the forensic evaluation of both the cause of death and accident dynamics needs to consider several factors, such as the child’s age, the type of restraint system employed, and the specific passenger seat occupied. Considering the complexity of the factors that can be involved in this road accident, it is crucial that there is a comprehensive exchange of information between the judge and the medical expert.
Crashes involving heavy trucks on rural mountainous freeways are known to result in severe injuries and fatalities, particularly under challenging driving conditions. This study aims to develop a robust model to accurately predict fatal and injury crashes involving heavy trucks on rural mountainous freeways. The crash database of Interstate-80 in Wyoming was used to extract a wide range of variables related to environmental, roadway, crash, occupant, and vehicle characteristics. This study employed a state-of-the-art deep neural network architecture named ResNet-50 using transfer learning to develop crash severity prediction models. The numeric crash data were converted to images utilizing DeepInsight to facilitate the application of the proposed deep learning model. Due to the imbalanced nature of the crash severity data, this study employed random undersampling (RUS) and synthetic minority oversampling technique (SMOTE) data balancing techniques and investigated several data sampling ratios. A ratio of 1∶2∶2
(Fatal: Injury: PDO) combined with both RUS and SMOTE produced the best performance with recall values of 99.7%, 79.7%, and 79.3% for fatal, injury, and PDO crashes, respectively. This study also employed Boruta and extreme gradient boosting (XGBoost) to examine the significance of variables on crash severity. The findings revealed that the deployment of airbags, use of seatbelts, driver distraction, and driver conditions such as inattentiveness and fatigue, vehicle type, vertical grades, weather, and road surface conditions were the most critical variables contributing to the severity of crashes involving heavy trucks. Furthermore, this study developed several reduced truck-involved crash severity prediction models without significantly compromising the prediction performance. The proposed deep neural network model can provide accurate and timely prediction of fatal and injury crashes involving heavy trucks, which is beneficial for ensuring efficient collision management, avoiding secondary pile-up crashes, and facilitating prompt medical assistance.
div>The objective of this study was to compare head, neck, and chest injury risks between front and rear-seated Hybrid III 50th-percentile male anthropomorphic test devices (ATDs) during matched frontal impacts. Seven vehicles were converted to rear seat test bucks (two sedans, three mid-size SUVs, one subcompact SUV, and one minivan) and then used to perform sled testing with vehicle-specific frontal NCAP acceleration pulses and a rear seated (i.e., second row) Hybrid III 50th male ATD. Matched front seat Hybrid III 50th male ATD data were obtained from the NHTSA Vehicle Crash Test Database for each vehicle. HIC15, Nij, maximum chest acceleration, and maximum chest deflection were compared between the front and rear seat tests, as well as between vehicles with conventional and advanced three-point belt restraint systems in the rear seat. Additionally, a modified version of the NCAP frontal star rating was calculated for the front and rear seat tests. All injury metrics, except for chest acceleration, were higher in the rear seat compared to the front. In addition, injury thresholds were exceeded or nearly exceeded in the rear seat for Nij in three vehicles, chest acceleration in one vehicle, and chest deflection in three vehicles, while no thresholds were exceeded in the front seat. When comparing advanced and conventional restraints in the rear seat, all injury metrics were higher in the vehicles with conventional restraints. All vehicles with conventional restraints in the rear had a star rating of 1, while those with advanced restraints in the rear ranged from 2 to 3. Conversely, all vehicles had 5 stars for the front seat, except one that had 4 stars. Overall, these data highlight the disparity between front and rear seat occupant protection and the benefits of advanced rear seat safety restraints, and the need for future testing.</div
Injury severity studies typically rely on police-reported crash data to examine risk factors associated with traffic injuries. The police crash database includes essential information on roadways, crashes and driver-vehicle characteristics but may not contain accurate and sufficient information on traffic injuries. Despite sizable efforts on injury severity modelling, very few studies have employed hospital records to classify injury severities accurately. As such, the inferences drawn from the police-recorded injury severity classifications may be questionable. This study investigates factors affecting road traffic injuries of motor vehicle crashes in two approaches (1) police-reported injury severity data and (2) a data fusion approach linking police and hospital records. Data from 2015 to 2019 were collected from the Abu Dhabi Traffic Police Department and linked with hospital records by the Department of Health, Abu Dhabi. A total of 6,333 casualty crashes were categorised into non-severe, severe, and fatal crashes following police-reported data and non-hospitalised, hospitalised and fatal crashes based on the police-hospital linked data. The state-of-the-art random thresholds random parameters hierarchical ordered Probit models were then employed to examine the differences in factors affecting crash-injury severities between police-reported and police-hospital linked data. While there are similarities between these two approaches, there are numerous notable differences in injury severity factors. For instance, head-on collisions are associated with high crash-injury severities in the model with police-hospital linked data, but they tend to show low injury severities in the model with police-reported data. In addition, the police-reported approach identifies that crashes occurred in remote areas and angle collisions are associated with low injury severities, which is not intuitive. These findings highlight that modelling the misclassified injury severity in police crash data may lead to wrong estimations and misleading inferences. Instead, the data fusion approach of police-hospital linked data provides critical and accurate insights into road traffic injuries and is a valuable approach for understanding traffic injuries.
The main focus of this study was to develop a robust prediction model based on deep learning capable of providing timely predictions of injury and fatal crashes in adverse weather on rural mountainous freeways. This study leveraged a promising deep learning technique named ResNet18. To apply the proposed deep learning model, the numeric crash data were converted to images utilizing a cutting-edge method, called DeepInsight. In addition, considering the imbalanced nature of the crash data, this study leveraged two data balancing techniques, namely Random Under Sampling (RUS) and Synthetic Minority Oversampling Technique (SMOTE); and experimented with several data sampling ratios. The best prediction performance was found using a ratio of 1:2:2 (Fatal:Injury:PDO) coupled with both RUS and SMOTE, which produced an overall prediction accuracy of 99.3% and 80.5% for fatal and injury crashes, respectively. This study also investigated the importance of variables on crash severity, which revealed that driver residency, vehicle damage extent, airbag deployment, driver conditions, weather, and road surface conditions were the most important variables contributing to the severity of crashes. The proposed deep learning framework can provide an accurate prediction of fatal and injury crashes, which is crucial to ensuring effective traffic collision management.
Owing to the narrow rear-row space of compact cars, the head of a rear-seat occupant can easily hit against the headrest or the seatback of the front seat in frontal collisions, thereby causing injuries to the occupant. A prototype design of a new safety seat is proposed to increase the safety of rear-seat occupants. The aim of this study is to investigate the protective effects of the new safety seat and further optimise the rear-seat restraint system in 100% and 40% overlapped frontal collisions. First, a simulation model of the restraint system is developed and validated. Second, the effects of the original seat and the new safety seats with different torsional stiffness of the torsion spring on the injuries to a female rear-seat occupant are compared. Finally, the design parameters of the rear-seat restraint system are optimised globally to minimise injuries to the female rear-seat occupant. Compared with the original seat case, the head injury criterion HIC15 and thorax 3 ms resultant acceleration T3MS of the female rear-seat occupant in the new safety seat case reduce, whereas the neck injury criterion N ij increases. When the torsional stiffness of the torsion spring decreases gradually, HIC15 and T3MS decrease. The optimum torsional stiffness of the torsion spring determined via analysis is 10 N m/°. The optimal combination of the design parameters of the rear-seat restraint system is obtained. After optimisation, for the 100% overlapped collision, HIC15 and T3MS decrease by 40.20% and 5.75%, respectively, N ij decreases by 35.94% and the peak left and right femur forces ( F L and F R , respectively) decrease by 9.65% and 12.26%, respectively. For the 40% overlapped collision, HIC15 and T3MS reduce by 39.92% and 11.64%, respectively, and N ij , F L and F R decrease by 8.89%, 7.50% and 6.09%, respectively.
The objective of this study was to investigate the effect of sedan wheelbase size on the kinematics and injury severity of left rear-seat occupants by using the finite element (FE) modeling method. A total of 270 cases with detailed accidental information records were analyzed to define the influence laws of wheelbase size and impact speed on the injury of left rear-seat occupants. First, the THUMS (Ver. 4.0.2) FE model was used to reconstruct two small offset collisions with different wheelbases size and unbelted left rear-seat occupants, and the effectiveness of the accident model was verified. Then, seatbelts were added to the left rear-seat occupant models. Finally, LS-DYNA software was used to study the correlation among head and chest injury and five sedan wheelbases sizes (2300, 2450, 2600, 2750, and 2905 mm) at three impact velocities (54, 64, and 74 km/h). The results showed that the occupants’ chest injuries showed an upward trend at the impact velocity of 64 and 74 km/h when the wheelbases sizes was reduced to 2300 mm. This research illustrated that at higher impact velocities, excessively small wheelbases might increase the chest injury severity of left rear-seat occupants.
The rear-facing seat has become a potential seating configuration for the future autonomous vehicle, therefore the potential injury risk of a rear-facing occupant merits further investigation not only for adults, but also for children. The objectives of this study were to compare the child occupant injury risk on specific body regions in frontal and rear impact, and to investigate the effect of those crash conditions and occupant related factors on the occupant injury risk. Data from the NASS–CDS and CISS were studied for crashes during 2000–2019 involving model year 2000–2020 motor vehicles, including frontal and rear–end collision. The injury risk by specific body regions were compared by descriptive statistics. Logistic regression models were developed to examine the effects of various factors on injury risk, controlling for crash type (frontal impact and rear impact), vehicle impact speed, vehicle impact location, vehicle model year, and occupant gender, age, restraint use, and seating position. After controlling for the confounding factors, the children age 3–17 had higher injury risk than infant and toddler (age 0–2) (at MAIS 2+, OR 8.71, p < 0.001). The child occupant injury risk was higher in frontal impact than in rear impact (at MAIS 2+, OR 4.96, p < 0.001), especially for children age 3–17 with the exception of the MAIS 1+ neck/spine injury risk. This study provided child injury risk references for current vehicle which may provide insight to the potential injury risk of rear-facing child occupant in future vehicle configurations.
The publics’ transit trip frequency determines the demand for urban public transit directly. The accuracy of forecasting plays a key role in planning and improvement of public transport system. To build a prediction model of public transit trip frequency on the basis of limited data survey, taking the public transit trip frequency as the research object, selecting independent variables from the characteristics of residents, and the public transport service level. Predicting the model by using ordinal logistic regression and validating the model through the parallelism test, the Wald test and verification test. Taking Taiyuan as an example, 723 valid questionnaires have been collected by issue questionnaires in four locations. The results show that: three independent variables including residents’ age, average monthly income, and travel time period are significantly related to the public transit trip frequency. The forecasting model is of statistical significance, and the forecasting accuracy rate is about 60.44%.
Female and male drivers have different size proportions and anthropometry. However, in the United States and throughout the world, male crash dummies are the norm in vehicle testing and female crash dummies with representative anthropometric characteristics has not yet been used in testing to date. Given this discrepancy, female driver safety is not considered at the same level as male driver safety in the vehicle design and testing process. This research investigates the gap in literature of injury locations experienced by female and male drivers in comparable crashes using a newly created linked dataset of crash and emergency medical services (EMS) data in the Commonwealth of Massachusetts. Generalized linear regression and k-fold cross validation of over 26,000 unique crash cases were analyzed using explanatory and predictive methods. These analyses revealed that female drivers are more likely to experience their primary anatomic injury as an abdomen, chest, lower extremity, and upper extremity injury than male drivers. The results of this research can be used by researchers, vehicle designers, and policymakers to act upon these differences in injury outcomes and consider them in the development of a safe environment for all roadway users.
Record linkage of health data has been beneficial to inform the design, delivery and evaluation of health care practices, and to improve the quality of clinical care and patient outcomes. We discuss some of the key strengths and limitations of using record linkage as the basis of an evidentiary approach for improved health services, and for conducting health services research. We illustrate the benefits of linking information from disparate administrative data collections, uncovering new knowledge, and influencing health policy or clinical practice, or both. Continued advancement of data methods and models, infrastructure to support research, and, above all, making administrative data accessible, will help ensure more effective delivery of health care services.
Drowsy driving is a significant crash risk factor. In 2006–2012, 22.5% of all crashes and 33.3% of fatal crashes were caused by drowsy driving in South Korea. This study examined driver, vehicle, road, weather, and temporal characteristics associated with drowsy-driving crashes in South Korea. This study found that drowsy-driving crashes were often caused by drivers in their thirties through fifties unlike the United States and other Western countries. The multinomial logit model on the crash severity of drowsy-driving crashes showed that older drivers age 60+, male drivers, and vans were more likely to be involved in fatal crashes. Also, the fatal crashes were more likely to occur in work zones, freeway segments with concrete barriers or no shoulder, and the month of August. These findings indicate that it is critical to implement road safety measures, such as rumble strips, in work zones and the areas with a high frequency of drowsy-driving crashes as well as safe and accommodating rest areas to prevent drowsy driving.
Traumatic events may lead to lumbar spine injuries ranging from low severity bony fracture to complex fracture dislocation. Injury pathomechanisms as well as the influence of loading rate and ligament mechanical properties were not yet fully elucidated. The objective was to quantify the influence of impact velocity and ligament properties variability on the lumbar spine response in traumatic flexion-shear conditions. An L1-L3 finite element spinal segment was submitted to a posterior-anterior impact at three velocities (2.7, 5, or 10 m/s) and for 27 sets of ligament properties. Spinal injury pathomechanism varied according to the impact velocities: initial osseous compression in the anterior column for low and medium velocities versus distraction in the posterior column for high velocity. Impact at 2.7 and 5 m/s lead to higher extent of bony injury, i.e., volume of ruptured bone, compared to the impact at 10 m/s (1140, 1094, and 718 mm3 respectively), lower L2 anterior displacement (2.09, 5.36, and 7.72 mm respectively), and lower facet fracture occurrence. Ligament properties had no effect on bony injury initiation but influenced the presence of facet fracture. These results improve the understanding of lumbar injury pathomechanisms and provide additional knowledge of lumbar injury load thresholds that could be used for injury prevention.
Stress distribution analysis at the injury initiation and final injury pattern identification for a lumbar segment submitted to a traumatic posterior-anterior impact.
This study describes injury patterns and outcomes related to the seating position of child passengers involved in motor vehicle crashes in Japan. Using data obtained from a national trauma registry database, we compared the occurrence of injuries by body parts, length of hospital stay and in-hospital deaths between front-seating and rear-seating among children. We analysed 166 children aged 0–5 years and 205 children aged 6–12 years. No significant differences were observed between front- and rear-seating for injured body parts, length of hospital stay or in-hospital deaths in the 0–5-year-old victims. Among those aged 6–12 years, rear-seating was associated with a higher incidence of head and chest injuries but the length of stay or in-hospital deaths did not differ. These findings contrast those of previous studies, which found that rear-seating reduces injury risk, possibly attributed to low age-appropriate restraint use among school-aged children in Japan.
Motor vehicle collisions (MVCs) are a significant cause of pediatric morbidity, particularly in low- to middle-income countries. We describe car seat use in children on the USA-Mexico border. A retrospective review was conducted for children 0-9 years old, admitted to the region's only Level I trauma center. Simultaneously, data were obtained from the SAFE KIDS database, a program that encourages car seat use through city checkpoints. There were 250 MVC admissions and nine fatalities in children 0-9 years old from 2010 to 2015. Nine percent of MVCs occurred in Mexico and 49% in El Paso, TX. Comparing trauma admissions to SAFE KIDS, there was some correlation between the location of MVCs and screening checkpoints (r = .50). There was a weaker correlation between injured children's neighborhoods and screening locations (r = .32). Only 37% of parents knew the crash history of the car seat and 3% were using a car seat previously involved in an MVC. While 96% of inspected children were placed appropriately in the backseat, 80% of children were found to be inappropriately restrained. Younger children more likely to be restrained (p < .05). Children from New Mexico and Mexico had the lowest rates of proper restraint and the highest injury severity scores. Proper use of car seats is a public health concern on the USA-Mexico border, and children are not properly restrained. Screening may be improved by focusing where at-risk children live and where most accidents occur. Restraint education is needed, particularly in New Mexico and Mexico.
To determine the effects of seating position, combined with restraint use and airbag status, on children's risk of dying in crashes.
Using 1988-95 data from the United States Fatality Analysis Reporting System, risk of death was compared among front and rear seated passengers aged 12 and younger who were involved in fatal crashes for different categories of restraint use and in vehicles with and without passenger airbags.
Restrained children in rear seats had the lowest risk of dying in fatal crashes. Among children seated in the rear, risk of death was reduced 35% in vehicles without any airbags, 31% in vehicles equipped only with driver airbags, and 46% in vehicles with passenger airbags. Both restrained and unrestrained children aged 0-12 were at lower risk of dying in rear seats. Rear seats also afforded additional protection to children aged 5-12 restrained only with lap belts compared with lap/shoulder belted children in front seats. Children were about 10-20% less likely to die in rear center than in rear outboard positions.
Parents and others who transport children should be strongly encouraged to place infants and children in rear seats whether or not vehicles have airbags. Existing laws requiring restraint use by children should be strengthened and actively enforced.
To assess the performance of the International Classification of Diseases (ICD) based injury severity score, ICISS, when applied to two versions of the 10th edition of ICD, ICD-10 and ICD-10-AM.
ICISS was assessed on its ability to predict threat to life using logistic regression modelling. Models used ICISS and age as predictors and survival as the outcome.
Australia and New Zealand. Patients or
Hospitalisations with an ICD-10-AM principal diagnosis in the range S00-T89 from 1 July 1999 to 30 June 2001 (Australia) or 1 July 1999 to 31 December 2001 (New Zealand).
None.
The models were assessed in terms of their discrimination, measured by the concordance score, and calibration, measured using calibration curves and the Hosmer-Lemeshow statistic.
523 633 Australian and 124 767 New Zealand hospitalisations were selected, including 7230 and 1565 deaths respectively. Discrimination was high in all the fitted models with concordance scores of 0.885 to 0.910. Calibration results were also promising with all calibration curves being close to linear, though ICISS appeared to underestimate mortality somewhat for cases with an ICISS score less than 0.6. Overall ICISS performed better when applied to the Australian than the New Zealand hospitalisations. Australian and New Zealand hospitalisations were very similar. ICISS was also only a little more successful when ICD-10-AM rather than mapped ICD-10 was used.
ICISS appears to be a reasonable way to estimate severity for databases using ICD-10 or ICD-10-AM. It is also likely to work well for other clinical variants of ICD-10.
This chapter primarily considers the analysis of measurements made on ordered categorical scales. It describes how unordered categorical data can be analysed. The chapter illustrates the application of mixed categorical models, and outlines ordinal logistic regression. Ordinal logistic regression is often preferable to contingency table methods such as the Chi-squared ‘test for trend’ because several fixed effects can be included in the model. It is extended to a mixed ordinal logistic regression model. The residual matrix for mixed categorical models has a more complex form than for generalized linear mixed models (GLMMs). A quasi-likelihood function for the model is defined, and model fitting methods are discussed. The chapter examines how the model can be adapted to analyse unordered categorical data. It considers some practical issues related to model fitting and interpretation, and gives a worked example.
Advanced mathematical and statistical computational methods are required by the LHC experiments for analyzing their data. Some of these methods are provided by the ROOT project, a C++ Object Oriented framework for large scale data handling applications. We review the current mathematical and statistical classes present in ROOT, emphasizing the recent developments.
The National Automotive Sampling System's Crashworthiness Data System (NASS CDS) was used to study rear occupant injuries in frontal crashes. The risks of injury for the rear passengers of different age groups were calculated and compared to the risks of injury for the front occupants. Furthermore, the risks of injury were investigated for the rear and front adult occupants over model years of vehicles. Distribution of injuries among body regions and vehicle contact points were also investigated for the rear adult occupants. While the rear occupants were more protected than the front occupants in most of the groups studied, an increasing trend was observed in the risk of injury of the rear adult occupants over the model years of the vehicles.
Objective:
To compare the pattern of injuries to front and rear seat occupants and test the hypothesis that rear seat passengers of different ages sustain different patterns of injury.
Method:
Patients admitted to a hospital following involvement in a crash in New South Wales (NSW) Australia between 2005 and 2007 were identified using International Classification of Diseases (10th edition [ICD10]) codes. Hospital admissions data were linked with NSW police crash data using probabilistic techniques. The profiles and patterns of injury of front and rear seat passengers were compared. Logistic regression was used to examine how age influenced the pattern of injury among rear seat passengers.
Results:
Sixty-three percent of hospital admissions were linked with police records. One in 5 passengers were rear seat passengers. There were more unrestrained occupants in the rear (7%) compared to drivers (3%) and front seat passengers (2%). Younger (9-15 years) injured passengers were seated in the rear more often than in the front passenger position and older injured passengers (>50 years) were seated more often in the front passenger position than in the rear (15% rear compared to 5% front aged 9-15 years; 22% rear compared to 37% front aged >50 years; χ(2), P < .001). There were proportionally more fatal injuries among rear seat passengers (10%) than among drivers (5%) and front seat passengers (6%), and the pattern of injury between front and rear passengers also varied. Rear seat passengers had more head and abdominal injuries and fewer thoracic and knee/lower leg injuries than front seat passengers. After adjusting for vehicle age, restraint status, travel speed, and whether or not a fatality occurred in the crash, older (>50 years) rear passengers had 6.3 times the odds of sustaining thoracic injuries (95% confidence interval [CI], 2.6-15.0) and lower odds (odds ratio [OR] = 0.4, 95% CI, 0.2-0.9) of sustaining abdominal/lumbar injuries than the youngest occupants (9-15 years).The odds of sustaining a head injury did not vary with age, and the odds of sustaining thoracic, abdominal, or lower extremity injuries did not differ significantly between rear seat passengers aged 16-50 years and 9-15 years.
Conclusions:
The findings suggest that there is a need for enhanced protection for rear seat passengers, because they have proportionally more fatal injuries than front-seated occupants. The frequency of abdominal injury and the differences between injury patterns observed in front seat passengers suggests a potential benefit from adding abdominal injury risk assessment to rear seat occupant protection test protocols. There is also scope to improve chest protection for older rear seat passengers.
Previous research has shown that rear seat occupant protection has decreased over model years, and front-end stiffness is a possible factor causing this trend. In this research, the effects of a change in stiffness on protection of rear seat occupants in frontal crashes were investigated. The stiffness was adjusted by using higher strength steels (DP and TRIP), or thicker metal sheets. Finite element simulations were performed, using an LS Dyna vehicle model coupled with a MADYMO dummy. Simulation results showed that an increase in stiffness, to the extent it happened in recent model years, can increase the risk of AIS3+ head injuries from 4.8% in the original model (with a stiffness of 1000N/mm) to 24.2% in a modified model (with a stiffness of 2356N/mm). The simulations also showed an increased risk of chest injury from 9.1% in the original model to 11.8% in the modified model. Distribution of injuries from real world accident data confirms the findings of the simulations.
The Department of Health and Human Services (HHS) released a proposed regulation that would replace the ICD-9-CM code sets currently used to report health care diagnoses and procedures with a new, expanded ICD-10 coding system.
Effectiveness of the rear seat in protecting occupants of different age groups in frontal crashes for 2000-2009 model years (MY) of vehicles was estimated and compared to 1990-1999 model years of vehicles. The objective was to determine the effectiveness of the rear seat compared to the front seat for various age groups in newer model year vehicles. The double paired comparison method was used to estimate relative effectiveness. For belted adults of the 25-49 age group, the fatality reduction effectiveness of the rear seat compared to the right front seat was 25 % (CI 11% to 36%), in the 1990-1999 model year vehicles. The relative effectiveness was -31% (CI -63% to -5%) for the same population, in the 2000-2009 model year vehicles. For restrained children 0-8 years old, the relative effectiveness was 55% (CI 48% to 61%) when the vehicles were of the 1990-1999 period. The level of effectiveness for this age group was reduced to 25% (CI -4% to 46%) in the 2000-2009 MYs of vehicles. Results for other age groups of belted occupants have followed a similar trend. All belted adult occupants of 25+ years old were significantly less protected in rear seats as compared to right front seats in the 2000-2009 model years of vehicles. For unbelted occupants however, rear seats were still a safer position than front seats, even in the 2000-2009 model years of vehicles.
The International Classification of Diseases Injury Severity Score (ICISS) has been proposed as an International Classification of Diseases (ICD)-10-based alternative to mortality prediction tools that use Abbreviated Injury Scale (AIS) data, including the Trauma and Injury Severity Score (TRISS). To date, studies have not examined the performance of ICISS using Australian trauma registry data. This study aimed to compare the performance of ICISS with other mortality prediction tools in an Australian trauma registry.
This was a retrospective review of prospectively collected data from the Victorian State Trauma Registry. A training dataset was created for model development and a validation dataset for evaluation. The multiplicative ICISS model was compared with a worst injury ICISS approach, Victorian TRISS (V-TRISS, using local coefficients), maximum AIS severity and a multivariable model including ICD-10-AM codes as predictors. Models were investigated for discrimination (C-statistic) and calibration (Hosmer-Lemeshow statistic).
The multivariable approach had the highest level of discrimination (C-statistic 0.90) and calibration (H-L 7.65, P= 0.468). Worst injury ICISS, V-TRISS and maximum AIS had similar performance. The multiplicative ICISS produced the lowest level of discrimination (C-statistic 0.80) and poorest calibration (H-L 50.23, P < 0.001).
The performance of ICISS may be affected by the data used to develop estimates, the ICD version employed, the methods for deriving estimates and the inclusion of covariates. In this analysis, a multivariable approach using ICD-10-AM codes was the best-performing method. A multivariable ICISS approach may therefore be a useful alternative to AIS-based methods and may have comparable predictive performance to locally derived TRISS models.
Previous studies have suggested that rear seat occupants are at lower risk of serious injury and death in crashes. However, over the last 10-15 years there have been significant changes in front seat safety systems. The aim of this study was to determine whether there is still a benefit for rear seated occupants compared to front seat occupants. A matched-cohort approach, using data on restrained occupants from the US National Automotive Sampling System (data years 1993-2007), was adopted. Conditional poisson regression modeling was used to evaluate the relative risk of AIS3+ injury in front (passenger and driver) and rear seat occupants, in vehicles of model year 1990-1996 compared to newer vehicles. Occupant age, belt type, and intrusion were additional variables in the model. The relative risk of AIS3+ injury for front and rear occupants was influenced by age and model year. For those aged 16-50 years in older vehicles, the front and rear seat offered similar levels of protection (RR=1.14, CI=1.09-1.19), however in newer model vehicles (1997-2007), the rear seat carried a higher risk of injury (RR=1.98, CI=1.90-2.06). For adults over 50 years, the rear seat carried a higher risk in both older and newer vehicles, and for 9-15 year olds, the rear seat carried a lower risk. These findings suggest that safety for front seat occupants has improved over the last decade, to the point where, for occupants over 15 years of age, the front seat is safer than the rear seat. While the benefit of rear seating for children aged 9-15 years has decreased over time, they are still at lower risk in the rear seat.
In this study, the level of protection offered to rear seat occupants in frontal crashes is investigated. The Fatality Analysis Reporting System (FARS) and National Automotive Sampling System Crashworthiness Data System (NASS CDS) databases were used for the analyses. The investigation focused on: 1- estimating the fatality protection effectiveness of the rear seat position relative to the right front seat position, using the double paired comparison method, 2- evaluating the effect of control group selection method on effectiveness predictions, and 3- identifying trends in rear seat occupant protection over model years of vehicles. By applying a uniform control group to the double paired comparison analysis of FARS data, this study suggests that all ages of occupants are safer in the rear seat than in the right front seat. Effectiveness estimates ranged from 5.9% to 82% for different age groups of occupants. Results indicate that although occupants overall benefit from sitting in the rear seat compared to the right front seat, for all model year vehicles, the protective effect of the rear seat relative to that of the right front seat has decreased in the newer model year vehicles. The reduction in the effectiveness was 43.7% for unbelted occupants and 33.5% for belted occupants. Logistic regression analysis on NASS CDS data shows that vehicle model year has a significant effect (p-value = 0.0043) on increasing the risk of injury for belted rear seat occupants. Considering these results, protection of rear seat occupants deserves more attention from the automotive industry and government agencies.
This study investigated the survival rates of occupants of passenger cars involved in a fatal crash between 2000 and 2003.
The information from every fatal crash in the United States between 2000 and 2003 was analyzed. Variables such as seat position, point of impact, rollover, restraint use, vehicle type, vehicle weight, occupant age, and injury severity were extracted from the Fatality Analysis Reporting System (FARS). Univariate and a full logistic multivariate model analyses were performed.
The data show that the rear middle seat is safer than any other occupant position when involved in a fatal crash. Overall, the rear (2(nd) row) seating positions have a 29.1% (Univariate Analysis, p<.0001, OR 1.29, 95% CI 1.22 - 1.37) increased odds of survival over the first row seating positions and the rear middle seat has a 25% (Univariate Analysis, p<.0001, OR 1.25, 95% CI 1.17 - 1.34) increased odds of survival over the other rear seat positions. After correcting for potential confounders, occupants of the rear middle seat have a 13% (Logistic Regression, p<.001, 95% CI 1.02 - 1.26) increased chance of survival when involved in a crash with a fatality than occupants in other rear seats.
This study has shown that the safest position for any occupant involved in a motor-vehicle crash is the rear middle seat.
The results of this research may impact how automobile manufacturers look at future rear middle seat designs. If the rear seat was to be designed exactly like its outboard counterparts (headrest, armrests, lap and shoulder belt, etc.) people may choose to sit on it more often rather than waiting to use it out of necessity due to multiple rear seat occupants.
To assess whether the use of integrated hospitalization and mortality data sources and/or the inclusion of comorbidity improve the predictive ability of the International Classification of Disease (ICD)-based Injury Severity Score (ICISS).
Models using either the ICISS based solely on hospital discharge data or one of nine modified ICISSs as the predictor variable were assessed on their ability to predict survival using logistic regression modeling.
New Zealand. Patients or
Inpatients, with an S00-T89 ICD-10-AM principal diagnosis, and fatalities, with any S00-T89 ICD-10-AM diagnosis, occurring in 2000-2003.
None.
Models were compared in terms of their discrimination (concordance), calibration, and goodness-of-fit.
186 835 cases including 9968 deaths met the inclusion criterion. The modified ICISS that included both mortality data and Charlson comorbid conditions at the ICD-10-AM level had the best concordance and high calibration. Calibration curves indicated that scores using hospital discharge data only to calculate survival risk ratios underestimated mortality, whereas scores using hospital discharge and mortality data overestimated mortality.
Valid measurement of injury severity is important for both meaningful research and surveillance and to assist in classifying information to meet specific injury policy, prevention, and control needs. This study suggests that the predictive ability of ICISS would be improved if both mortality and comorbidity data were included in its calculation.
The Ninth Revision of the International Classification of Diseases is to come into use on 1st January, 1979. Volume 1, the classification itself, with notes and rules on its use, will be on sale soon; and Volume 2, the alphabetical index, should be available in the summer. The ICD is used in hospitals for classifying diagnostic information in Hospital Activity Analysis/Hospital Inpatient Enquiry summaries, which are the basis of local and national statistics and for diagnostic indexes. It is also used for coding diagnostic data for a variety of other health-care, morbidity and mortality information, both on a regular basis for ad hoc surveys. The intention of this article is to give a little more detail of the background to the revision, its implementation, the changes and new features in the classification and the new international rules for selection of the main condition for routine tabulations of morbidity.
Does a database of hospital admission data linked to police road traffic accident (RTA) reports produce less biased information for the injury prevention policymaker, planner, and practitioner than police RTA reports alone?
Data linkage study.
Non-fatal injury victims of road traffic crashes in southern England who were admitted to hospital.
Hospital admissions and police RTA reports.
The estimated proportion of road traffic crashes admitted to hospital that were included on the linked database; distributions by age, sex, and road user groups: (A) for all RTA injury admissions and (B) for RTA serious injury admissions defined by length of stay or by nature of injury.
An estimated 50% of RTA injury admissions were included on the linked database. When assessing bias, admissions data were regarded as the "gold standard". The distributions of casualties by age, sex, and type of road user showed major differences between the admissions data and the police RTA injury data of comparable severity. The linked data showed smaller differences when compared with admissions data. For RTA serious injury admissions, the distributions by age and sex were approximately the same for the linked data compared with admissions data, and there were small but statistically significant differences between the distributions across road user group for the linked data compared with hospital admissions.
These results suggest that investigators could be misinformed if they base their analysis solely on police RTA data, and that information derived from the linked database is less biased than that from police RTA data alone. A national linked dataset of road traffic crash data should be produced from hospital admissions and police RTA data for use by policymakers, planners and practitioners.
Using US data for 1986-1998 fatal crashes, we employed matched-pair analysis methods to estimate that the relative risk of death among belted compared with unbelted occupants was 0.39 (95% confidence interval (CI) 0.37-0.41). This differs from relative risk estimates of about 0.55 in studies that used crash data collected prior to 1986. Using 1975-1998 data, we examined and rejected three theories that might explain the difference between our estimate and older estimates: (1) differences in the analysis methods; (2) changes related to car model year; (3) changes in crash characteristics over time. A fourth theory, that the introduction of seat belt laws would induce some survivors to claim belt use when they were not restrained, could explain part of the difference in our estimate and older estimates; but even in states without seat belt laws, from 1986 through 1998, the relative risk estimate was 0.45 (95% CI 0.39-0.52). All of the difference between our estimate and older estimates could be explained by some misclassification of seat belt use. Relative risk estimates would move away from 1, toward their true value, if misclassification of both the belted and unbelted decreased over time, or if the degree of misclassification remained constant, as the prevalence of belt use increased. We conclude that estimates of seat belt effects based upon data prior to 1986 may be biased toward 1 by misclassification.
Standard analysis of matched-pair cohort data requires information only from pairs in which at least one had the study outcome. This can be useful in traffic fatality studies of characteristics that can vary among vehicle occupants, such as seat belt use, as crash databases often lack information about vehicles in which all survived. However, matching crash victims who were in the same vehicle does not necessarily eliminate confounding by vehicle or crash related factors, because the matched occupants must be in different seat positions. This paper reviews three methods for estimating relative risks in matched-pair crash data. The first, Mantel-Haenszel stratified methods, may produce biased estimates if seat position is associated with the outcome. The second, the double-pair comparison method, was designed to deal with confounding by seat position. If the effects of seat position vary according to some vehicle or crash characteristic which is associated with the study exposure, adjustment for this characteristic may be needed to produce unbiased estimates. Third, conditional Poisson regression and Cox proportional hazards regression can produce unbiased estimates, but may require model interaction terms between seat position and vehicle or crash characteristics. This paper reviews some of the strengths and limitations of each of these methods, and illustrates their use in simulated and real crash data.
To estimate the association of passenger seat position with the risk of death and serious injury for passengers in traffic crashes.
Using 1993-2000 data from the National Highway Traffic Safety Administration's Crashworthiness Data System (CDS), the risk ratio for death and serious injury was estimated for rear seat passengers compared with front seat passengers in motor vehicle crashes.
The adjusted risk ratio for death of passengers in the rear seat in a crash was 0.61 (95% confidence interval (CI) 0.46-0.81). Rear seat passenger position was also associated with a decrease in the risk of death and serious injury compared with the front seat passenger position: risk ratio=0.67 (95% CI 0.57-0.78).
We estimated that the rear seat passenger position may reduce the risk of death in a motor vehicle crash by about 39% and reduce the risk of death or serious injury in a crash by 33%, compared with the front seat passenger position. If the associations that we report are causal, sitting in the rear seat, compared with the front seat, may prevent about 4 in 10 passenger deaths, or 3 in 10 passenger deaths and injuries, that might otherwise occur.
To estimate the association of passenger seating position with the risk of death for passengers in traffic crashes. Design, setting,
Matched cohort analysis of data from the National Highway Traffic Safety Administration Fatality Analysis Reporting System regarding 56 644 passengers in 23 308 passenger cars, light trucks, vans, and sport utility vehicles that crashed during 1990-2001.
The adjusted risk ratio (aRR) for death of a rear seat passenger compared with a front seat passenger within 30 days of a crash.
The aRR for all passengers in the rear seat in a crash was 0.79 (95% CI 0.77 to 0.82). This estimate varied by age, restraint use, and the presence of a front passenger airbag (p<0.001). For restrained passengers in cars with a front passenger airbag, the aRR was 0.62 (95% CI 0.48 to 0.81) for children 0-12 years, 0.96 (95% CI 0.88 to 1.06) for passengers 13-29 years, 1.03 (95% CI 0.93 to 1.15) for passengers 30-59 years, and 1.06 (95% CI 0.90 to 1.26) for passengers 60 years or older. The rear seat was associated with more protection in cars without front airbags and more protection for unrestrained passengers compared with restrained passengers.
Previous studies have reported that the rear seat was safer for persons of all ages; thus seating a young child in the rear has often meant that older children and adults had to assume an increased risk of death by sitting in the front. These results suggest that when front passenger airbags are present and passengers are restrained, putting adults in front and children in back enhances child safety without sacrificing adult safety.
To investigate the relationship between restraint usage and injury outcome in child motor vehicle occupants aged 2-8 years.
Retrospective case review of all child occupants presenting at the Children's Hospital at Westmead between July 2002 and January 2005 subsequent to a motor vehicle crash. Injury severity was assessed in terms of the Abbreviated Injury Scale (AIS), by age and type of restraint.
Data were collected for 152 child occupants aged 2 and 8 years. While nearly all children (94%) used some restraint, most (82%) used a suboptimal form of restraint. Injury severity between optimally restrained children and suboptimally restrained children differed significantly (Fisher's exact test, P<0.001), with suboptimally restrained children receiving a greater proportion of moderate to severe (AIS 2+) injuries. No optimally restrained child sustained an AIS 2+ injury.
A total of 82% of child occupants aged 2-8 years involved in crashes were suboptimally restrained. All children who sustained serious injuries were suboptimally restrained. There is a need to encourage correct use of the most appropriate restraint for child motor vehicle occupants in order to reduce the number and severity of injuries in these road users.
In most countries, epidemiologic knowledge of road crash injury is mainly based on police data, as they very often are the only available data at the nation-wide level. However their validity is of some concern. We focus here on the police severity classification of 'serious' and 'slight' casualties in France. We want to know how the police classification compares with a trauma severity scale, so that we could correctly interpret police based studies.
The study is based on the Rhône county (population 1.6 million) during the 1997 to 2001 period. Police data have been linked with a road trauma registry, so that both police and New Injury Severity Score (NISS) classifications are available on 14,342 casualties. The police classification of 'slight' and 'serious' casualties is compared with the registry classification grouped into NISS 1-15 and NISS 16-75 categories. We conduct multivariate analyses of the probability of police severity misclassification, over and under-classification, as a function of crash and casualty characteristics.
Kappa is estimated at 0.41; the sensitivity of the police classification is 72% and the positive predictive value is 35%. Pedestrian and motorcyclist casualties are the most likely to be over-classified (Relative Risk [RR] = 1.4 and RR = 1.2, respectively compared with car occupants). The 'rural police' are more likely to over-classify than the other police forces (RR = 3.1). Over-classification decreased during the 1997 to 2001 period whereas under- classification increased.
These misclassification characteristics must be kept in mind when interpreting severity results based on police data. We are working on obtaining unbiased nation-wide estimates of severity figures.
Car crashes are a major cause of death and serious injury to children but most analyses of risk are based on US data. The Australian context is different in at least three ways: (1) the proportion of passenger-side airbags, a potential risk to children in front seats, is much lower; (2) unlike in the US, Australian airbags are designed to work with restrained passengers; (3) restraint use for children 0-12 years is high (>90%). Official data drawn from Victorian crash records (n=30,631) were used to calculate relative risks of death or serious injury for children (0-3 years, 4-7 years; 8-12 years) traveling in passenger cars during 1993-1998 and 1999-2004. Over 90% were reportedly wearing a restraint, and 20% were traveling in the front seat. For children under 4 years traveling in the front seat, the relative risk of death was twice as great as when traveling in the rear, and that of serious injury was 60% greater. The relative risk of death whilst traveling in the front seat was almost four times greater for children aged under 1 year. We suggest that serious consideration should be given to mandating rear seating for children, particularly those aged 4 and under.
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