Motor Vehicle Crash Injuries Research Articles

Occupant-to-occupant contact injury in motor vehicle crashes

ABSTRACTObjective: This is a descriptive study of the frequency and risk of occupant-to-occupant contact injury by crash type and occupant age. It focused on rear impacts because of a recent Senate inquiry.Methods: 1994–2013 NASS-CDS data were used to investigate the effects of occupant-to-occupant contact on the risk of serious-to-fatal injury (Abbreviated Injury Scale [AIS] 3+) by crash type and age group. NASS-CDS in-depth cases were analyzed to identify crash circumstances for AIS 3+ occupant-to-occupant contact injury in rear crashes.Results: Serious injury (AIS 3+) due to occupant-to-occupant contact was uncommon. It represented only 0.84% of all AIS 3+ injury for all age groups. The overall risk of AIS 3+ occupant-to-occupant contact injury was 0.042 ± 0.007%. The highest incidence was in side impacts (69.8%) followed by rollovers (22.9%). Occupant-to-occupant contact injury risk was lower in rear impacts than in other crash types, at 0.0078 ± 0.0054%.The highest risk of AIS 3+ injury with occupant-to-occupant was for the <9-year-old age group when compared to other age groups for all crash types. The risk was 0.051 ± 0.026%, representing 2.69% of all AIS 3+ injury in the <9-year-old age group. Only 4.2% of AIS 3+ occupant-to-occupant contact injury occurred to children <9 years old in rear impacts. The corresponding injury risk was lowest in rear impacts, at 0.014 ± 0.014%%, when compared to other crash types.The analysis of in-depth NASS-CDS cases of occupant-to-occupant contact injury in children< 9 years old involved in rear impacts identified very severe collisions in older model vehicles with deformation of the occupant compartment and yielding front seats as main factors for the contact injury. Front seat occupants injuring rear-seated children was not identified in the in-depth NASS-CDS cases.Conclusions: AIS 3+ occupant-to-occupant contact injury occurs primarily in side impacts and rollovers. Most contact injury is to adults (89.4% incidence). Occupant-to-occupant contact injury to children is rare in rear impacts.

Brainstem injury in motor vehicle crashes

ABSTRACTObjective: This is a descriptive study of the frequency and risk for brainstem injury by crash type, belt use, and crash severity (delta-V). NASS-CDS electronic cases were reviewed to see whether the transition from vehicles without advanced airbags and seat belts and side airbags and curtains to vehicles with the safety technologies has influenced the risk for brainstem injury.Methods: 1994–2013 NASS-CDS was analyzed to determine the number of brainstem injuries in nonejected adults (15+ years old) in vehicle crashes. Crashes were grouped by front, side, rear, and rollover. The effect of belt use was investigated. Light vehicles were included with model year (MY) 1994+. Occupants with severe head injury (Abbreviated Injury Scale [AIS] 4+) and Maximum Abbreviated Injury Scale (MAIS) 4+F injury were also determined. The risk for injury with standard errors was determined using the MAIS 0+F exposure by belt use and crash type. NASS-CDS electronic cases were studied with brainstem injury in 2001–2013 MY vehicles.Results: NASS-CDS indicates there are 872 ± 133 cases of brainstem injury per year. About 16.0% of AIS 4+ head injury involves the brainstem. For belted occupants, the highest risk for brainstem injury was in side impacts at 0.065 ± 0.010%. In contrast, the highest risk for brainstem injury was 0.310 ± 0.291% in rear impacts and 0.310 ± 0.170% in rollovers for unbelted occupants. The risk for brainstem injury increased with crash severity. The highest risk for brainstem injury was 3.54 ± 1.45% in crashes with >72 km/h (>45 mph) delta-V. Exponential functions fit the change in risk with delta-V. Eighteen NASS-CDS electronic cases showed that brainstem injury occurred in very severe collisions where the occupant experienced multiple injuries from intrusion or impact on vehicle structures stiffened by deformation.Conclusions: The risk for brainstem injury in belted occupants has remained essentially constant over 20 years, whereas the risk for MAIS 4+F injury has declined 38.3%. The prevention of brainstem injuries must address the extreme speed of collisions and weight mismatches that overwhelm structures, seat belts, frontal airbags, side airbags, and curtains in modern vehicles.

Disability risk in pediatric motor vehicle crash occupants.

Mortality rates among children in motor vehicle crashes (MVCs) are typically low; however, nonfatal injuries can vary in severity by imposing differing levels of short- and long-term disability. To better discriminate the severity of nonfatal MVC injuries, a pediatric-specific disability risk (DR) metric was created. The National Automotive Sampling System 2000 to 2011 was used to define the top 95% most common Abbreviated Injury Scale (AIS) 2+ injuries among pediatric MVC occupants. Functional Independence Measure scores were abstracted from the National Trauma Data Bank 2002 to 2006. Multiple imputation was used to account for missing data. The DR and coinjury-adjusted DR (DRMAIS) of the most common AIS 2+ MVC-induced injuries were calculated for 7-year-old to 18-year-old children by determining the proportion of those disabled after an injury to those sustaining the injury. DR and DRMAIS values ranged from 0 to 1, representing 0% to 100% DR. The mean DR and DRMAIS of all injuries were 0.290 and 0.191, respectively. DR and DRMAIS were greatest for injuries to the head (DR, 0.340; DRMAIS, 0.279), thorax (DR, 0.320; DRMAIS, 0.233), and spine (DR, 0.315; DRMAIS, 0.200). The mean DR and DRMAIS increased with increasing AIS severity but there was significant variation and overlapping values across AIS severity levels. Comparison of DRMAIS to coinjury-adjusted mortality risk (MRMAIS) revealed that among 118 injuries with MRMAIS of 0.000, DRMAIS ranged from 0.000 to 0.429. Incorporation of DR metrics into injury severity metrics may improve the ability to distinguish between the severity of different nonfatal injuries. This is especially crucial in the pediatric population where permanent disability can result in a high number of years lost due to disability. The accuracy of such severity metrics is crucial to the success of pediatric triage algorithms such as Advanced Automatic Crash Notification algorithms. Epidemiologic/prognostic study, level III.

Head injuries (TBI) to adults and children in motor vehicle crashes

ABSTRACTPurpose: This is a descriptive study. It determined the annual, national incidence of head injuries (traumatic brain injury, TBI) to adults and children in motor vehicle crashes. It evaluated NASS-CDS for exposure and incidence of various head injuries in towaway crashes. It evaluated 3 health databases for emergency department (ED) visits, hospitalizations, and deaths due to TBI in motor vehicle occupants.Methods: Four databases were evaluated using 1997–2010 data on adult (15+ years old) and child (0–14 years old) occupants in motor vehicle crashes: (1) NASS-CDS estimated the annual incidence of various head injuries and outcomes in towaway crashes, (2) National Hospital Ambulatory Medical Care Survey (NHAMCS)-estimated ED visits for TBI, (3) National Hospital Discharge Survey (NHDS) estimated hospitalizations for TBI, and (4) National Vital Statistics System (NVSS) estimated TBI deaths. The 4 databases provide annual national totals for TBI related injury and death in motor vehicle crashes based on differing definitions with TBI coded by the Abbreviated Injury Scale (AIS) in NASS-CDS and by International Classification of Diseases (ICD) in the health data.Results: Adults: NASS-CDS had 16,980 ± 2,411 (risk = 0.43 ± 0.06%) with severe head injury (AIS 4+) out of 3,930,543 exposed adults in towaway crashes annually. There were 49,881 ± 9,729 (risk = 1.27 ± 0.25%) hospitalized with AIS 2+ head injury, without death. There were 6,753 ± 882 (risk = 0.17 ± 0.02%) fatalities with a head injury cause. The public health data had 89,331 ± 6,870 ED visits, 33,598 ± 1,052 hospitalizations, and 6,682 ± 22 deaths with TBI. NASS-CDS estimated 48% more hospitalized with AIS 2+ head injury without death than NHDS occupants hospitalized with TBI. NASS-CDS estimated 29% more deaths with AIS 3+ head injury than NVSS occupant TBI deaths but only 1% more deaths with a head injury cause. Children: NASS-CDS had 1,453 ± 318 (risk = 0.32 ± 0.07%) with severe head injury (AIS 4+) out of 454,973 exposed children annually. There were 2,581 ± 683 (risk = 0.57 ± 0.15%) hospitalized with AIS 2+ head injury, without death. There were 466 ± 132 (risk = 0.10 ± 0.03%) fatalities with a head injury cause. The public health data had 19,251 ± 2,803 ED visits, 3,363 ± 255 hospitalizations, and 488 ± 6 deaths with TBI. NASS-CDS estimated 24% fewer hospitalized children with AIS 2+ head injury without death than NHDS hospitalization with TBI. NASS-CDS estimated 31% more deaths with AIS 3+ head injury than NVSS child deaths but 5% fewer deaths with a head injury cause.Conclusions: The annual national incidence of motor vehicle–related head injury (TBI) was estimated using 1997–2010 NASS-CDS from the Department of Transportation and NHAMCS (ED visits), NHDS (hospitalizations), and NVSS (deaths) from the Department of Health and Human Services. The transportation and health databases use different definitions and coding, which complicates direct comparisons. Future work is needed where ICD to AIS translators are used if comparisons of serious head injuries in NASS and health data sets are to be made.

Characterization of the occult nature of injury for frequently occurring motor vehicle crash injuries

BackgroundOccult injuries are not easily detected and can be potentially life-threatening. The purpose of this study was to quantify the perceived occultness of the most frequent motor vehicle crash injuries according to emergency medical services (EMS) professionals. Study designAn electronic survey was distributed to 1,125 EMS professionals who were asked to quantify the likelihood that first responders would miss symptoms related to a particular injury on a 5-point Likert scale. The Occult Score for each injury was computed from the average of all the survey responses and normalized to be a continuous metric ranging from 0 to 1 where 0 is a non-occult (highly apparent on initial presentation) injury and 1 is an occult (unapparent on initial presentation) injury. ResultsOverall, 110,671 survey responses were collected. The Occult Score ranged from 0 to 1 with a mean, median, and standard deviation of 0.443, 0.450, and 0.233, respectively. When comparing the Occult Score of an injury to its corresponding AIS severity, there was no relationship between the metrics. When stratifying by body region, injury type, and AIS severity, it was evident that AIS 2–4 abdominal injuries with lacerations, hemorrhage, or contusions were perceived as the most occult injuries. ConclusionsTimely triage is key to reduce the morbidity and mortality associated with occult injuries. The Occult Score developed in this study to describe the predictability of an injury in a motor vehicle crash will be used as part of a larger effort, including incorporation into an advanced automatic crash notification (AACN) algorithm to detect crash conditions associated with a patient’s need for prompt treatment at a trauma center.

Scaling approach in predicting the seatbelt loading and kinematics of vulnerable occupants: How far can we go?

ABSTRACTObjective: Occupants with extreme body size and shape, such as the small female or the obese, were reported to sustain high risk of injury in motor vehicle crashes (MVCs). Dimensional scaling approaches are widely used in injury biomechanics research based on the assumption of geometrical similarity. However, its application scope has not been quantified ever since. The objective of this study is to demonstrate the valid range of scaling approaches in predicting the impact response of the occupants with focus on the vulnerable populations.Methods: The present analysis was based on a data set consisting of 60 previously reported frontal crash tests in the same sled buck representing a typical mid-size passenger car. The tests included two categories of human surrogates: 9 postmortem human surrogates (PMHS) of different anthropometries (stature range: 147–189 cm; weight range: 27–151 kg) and 5 anthropomorphic test devices (ATDs). The impact response was considered including the restraint loads and the kinematics of multiple body segments. For each category of the human surrogates, a mid-size occupant was selected as a baseline and the impact response was scaled specifically to another subject based on either the body mass (body shape) or stature (the overall body size). To identify the valid range of the scaling approach, the scaled response was compared to the experimental results using assessment scores on the peak value, peak timing (the time when the peak value occurred), and the overall curve shape ranging from 0 (extremely poor) to 1 (perfect match). Scores of 0.7 to 0.8 and 0.8 to 1.0 indicate fair and acceptable prediction.Results: For both ATDs and PMHS, the scaling factor derived from body mass proved an overall good predictor of the peak timing for the shoulder belt (0.868, 0.829) and the lap belt (0.858, 0.774) and for the peak value of the lap belt force (0.796, 0.869). Scaled kinematics based on body stature provided fair or acceptable prediction on the overall head/shoulder kinematics (0.741, 0.822 for the head; 0.817, 0.728 for the shoulder) regardless of the anthropometry. The scaling approach exhibited poor prediction capability on the curve shape for the restraint force (0.494 and 0.546 for the shoulder belt; 0.585 and 0.530 for the lap belt). It also cannot well predict the excursion of the pelvis and the knee.Conclusions: The results revealed that for the peak lap belt force and the forward motion of the head and shoulder, the underlying linear relationship with body size and shape is valid over a wide anthropometric range. The chaotic nature of the dynamic response cannot be fully recovered by the assumption of the whole-body geometrical similarity, especially for the curve shape. The valid range of the scaling approach established in this study can be reasonably referenced in predicting the impact response of a given specific population with expected deviation. Application of this knowledge also includes proposing strategies for restraint configuration and providing reference for ATD and/or human body model (HBM) development for vulnerable occupants.

Functional outcomes of motor vehicle crash head injuries in pediatric and adult occupants

ABSTRACTObjective: The objective of the study was to develop a disability-based metric for motor vehicle crash (MVC) injuries, with a focus on head injuries, and compare the functional outcomes between the pediatric and adult populations.Methods: Disability risk (DR) was quantified using Functional Independence Measure (FIM) scores within the National Trauma Data Bank—Research Data System (NTDB-RDS) for the top 95% most frequently occurring Abbreviated Injury Scale (AIS) 3, 4, and 5 head injuries in NASS-CDS 2000–2011. Pediatric (ages 7–18), adult (19–45), middle-aged (46–65), and older adult (66+) patients with an FIM score available who were alive at discharge and had an AIS 3, 4, or 5 injury were included in the study. The NTDB-RDS contains a truncated form of the FIM instrument, including 3 items (self-feed, locomotion, and verbal expression), each graded on a scale of 1 (full functional dependence) to 4 (full functional independence). Patients within each age group were classified as disabled or not disabled based on the FIM scale. The DR was calculated for each age group by dividing the number of patients who sustained a specific injury and were disabled by the number of patients who sustained the specific injury. To account for the impact of more severe associated coinjuries, a maximum AIS (MAIS) adjusted DR (DRMAIS) was also calculated for each injury. DR and DRMAIS ranged from 0 (0% disability risk) to 1 (100% disability risk).Results: An analysis of the most frequent FIM components associated with disabling MVC head injuries revealed that disability across all 3 items (self-feed, locomotion, and expression) was the most frequent for pediatric and adult patients. Only locomotion was the most frequent for middle-aged and older adults. The mean DRMAIS for MVC head injuries was 35% for pediatric patients, 36% for adults, 38% for middle-aged adults, and 44% for older adults. Further analysis was conducted by grouping the head injuries into 8 groups based on the structure of injury and injury type. The pediatric population possessed higher DRMAIS values for brain stem injuries as well as loss of consciousness injuries. Older adults possessed higher DRMAIS values for contusion/hemorrhage injuries, epidural hemorrhage, intracerebral hemorrhage, skull fracture, and subdural/subarachnoid hemorrhage.Conclusion: At-risk populations such as pediatric and older adult patients possessed higher DRMAIS values for different head injuries. Disability in pediatric patients is critical due to loss of quality life years. Disability risk can supplement severity metrics to improve the ability of such metrics to discriminate the severity of different injuries that do not lead to death. Understanding of age-related differences in injury outcomes when compared to adults could inform future age-specific modifications to the AIS.

AMA Recommends Schools Start Later To Improve Teen Sleep

AMA Recommends Schools Start Later To Improve Teen Sleep

The Association of Gasoline Prices With Hospital Utilization and Costs for Motorcycle and Nonmotorcycle Motor Vehicle Injuries in the United States.

This study examined the association between gasoline prices and hospitalizations for motorcycle and nonmotorcycle motor vehicle crash (MVC) injuries. Data on inpatient hospitalizations were obtained from the 2001 to 2010 Nationwide Inpatient Sample. Panel feasible generalized least squares models were used to estimate the effects of monthly inflation-adjusted gasoline prices on hospitalization rates for MVC injuries and to predict the impact of increasing gasoline taxes. On the basis of the available data, a $1.00 increase in the gasoline tax was associated with an estimated 8348 fewer annual hospitalizations for nonmotorcycle MVC injuries, and reduced hospital costs by $143 million. However, the increase in the gasoline tax was also associated with an estimated 3574 more annual hospitalizations for motorcycle crash injuries, and extended hospital costs by $73 million. This analysis of some existing data suggest that the increased utilization and costs of hospitalization from motorcycle crash injuries associated with an increase in the price of gasoline are likely to substantially offset reductions in nonmotorcycle MVC injuries. A policy decision to increase the gasoline tax could improve traffic safety if the increased tax is paired with public health interventions to improve motorcycle safety.

An Injury Severity-, Time Sensitivity-, and Predictability-Based Advanced Automatic Crash Notification Algorithm Improves Motor Vehicle Crash Occupant Triage

Advanced Automatic Crash Notification algorithms use vehicle telemetry measurements to predict risk of serious motor vehicle crash injury. The objective of the study was to develop an Advanced Automatic Crash Notification algorithm to reduce response time, increase triage efficiency, and improve patient outcomes by minimizing undertriage (<5%) and overtriage (<50%), as recommended by the American College of Surgeons. A list of injuries associated with a patient's need for Level I/II trauma center treatment known as the Target Injury List was determined using an approach based on 3 facets of injury: severity, time sensitivity, and predictability. Multivariable logistic regression was used to predict an occupant's risk of sustaining an injury on the Target Injury List based on crash severity and restraint factors for occupants in the National Automotive Sampling System - Crashworthiness Data System 2000-2011. The Advanced Automatic Crash Notification algorithm was optimized and evaluated to minimize triage rates, per American College of Surgeons recommendations. The following rates were achieved: <50% overtriage and <5% undertriage in side impacts and 6% to 16% undertriage in other crash modes. Nationwide implementation of our algorithm is estimated to improve triage decisions for 44% of undertriaged and 38% of overtriaged occupants. Annually, this translates to more appropriate care for >2,700 seriously injured occupants and reduces unnecessary use of trauma center resources for >162,000 minimally injured occupants. The algorithm could be incorporated into vehicles to inform emergency personnel of recommended motor vehicle crash triage decisions. Lower under- and overtriage was achieved, andnationwide implementation of the algorithm would yield improved triage decision making for an estimated 165,000 occupants annually.

Motor Vehicle Crash (MVC) Case Definitions and How They Impact MVC Surveillance

Motor vehicle crashes (MVCs) are one of the leading causes of injury in the U.S. National injury surveillance is commonly captured using E-codes. However, use of E-codes alone to capture MVC-related ED visits may result in a different picture of MVC injuries compared to using text searches of triage or chief complaint notes. In this study, we identify and describe how the case definition used to identify MVC patients can impact results when conducting MVC surveillance. We compare MVC patients identified using E-codes, text searches, or both criteria together. We found that choice of case definition impacts the picture of MVC severity.

Observed child restraint misuse in a large, urban community: Results from three years of inspection events

ProblemChild restraints (CRs) are vital for optimizing child passenger safety and reducing the risk of pediatric injury and fatality in motor vehicle crashes. However, most CRs are installed improperly. MethodsThis present study was an assessment of observed instances of CR misuse. Participants were recruited through advertisements for CR inspection events in Los Angeles County, California. Child Passenger Safety Technicians collected information about each child passenger, vehicle, and aspects of CR selection and installation. ResultsOf 693 CRs installed upon arrival, only 3.8% were used with no instances of misuse. The most common misuses were inappropriate use of the top tether and failure to secure the seatbelt in locked mode. ConclusionsThe majority of observed CRs were installed with instances of misuse. CRs in newer vehicles were less likely to be installed in front of airbags and more likely to have the seatbelt routed inappropriately compared to those in older vehicles. Older children were more likely to be prematurely restrained in the front vehicle seat. Practical ApplicationsThe majority of CRs are installed improperly. We identified specific instances of CR misuse that are common in a large, urban community and present recommendations to improve child passenger safety practices and education.

Mortality Risk in Pediatric Motor Vehicle Crash Occupants: Accounting for Developmental Stage and Challenging Abbreviated Injury Scale Metrics

Objective: Survival risk ratios (SRRs) and their probabilistic counterpart, mortality risk ratios (MRRs), have been shown to be at odds with Abbreviated Injury Scale (AIS) severity scores for particular injuries in adults. SRRs have been validated for pediatrics but have not been studied within the context of pediatric age stratifications. We hypothesized that children with similar motor vehicle crash (MVC) injuries may have different mortality risks (MR) based upon developmental stage and that these MRs may not correlate with AIS severity.Methods: The NASS-CDS 2000–2011 was used to define the top 95% most common AIS 2+ injuries among MVC occupants in 4 age groups: 0–4, 5–9, 10–14, and 15–18 years. Next, the National Trauma Databank 2002–2011 was used to calculate the MR (proportion of those dying with an injury to those sustaining the injury) and the co-injury-adjusted MR (MRMAIS) for each injury within 6 age groups: 0–4, 5–9, 10–14, 15–18, 0–18, and 19+ years. MR differences were evaluated between age groups aggregately, between age groups based upon anatomic injury patterns and between age groups on an individual injury level using nonparametric Wilcoxon tests and chi-square or Fisher's exact tests as appropriate. Correlation between AIS and MR within each age group was also evaluated.Results: MR and MRMAIS distributions of the most common AIS 2+ injuries were right skewed. Aggregate MR of these most common injuries varied between the age groups, with 5- to 9-year-old and 10- to 14-year-old children having the lowest MRs and 0- to 4-year-old and 15- to 18-year-old children and adults having the highest MRs (all P <.05). Head and thoracic injuries imparted the greatest mortality risk in all age groups with median MRMAIS ranging from 0 to 6% and 0 to 4.5%, respectively. Injuries to particular body regions also varied with respect to MR based upon age. For example, thoracic injuries in adults had significantly higher MRMAIS than such injuries among 5- to 9-year-olds and 10- to 14-year-olds (P =.04; P <.01). Furthermore, though AIS was positively correlated with MR within each age group, less correlation was seen for children than for adults. Large MR variations were seen within each AIS grade, with some lower AIS severity injuries demonstrating greater MRs than higher AIS severity injuries. As an example, MRMAIS in 0- to 18-year-olds was 0.4% for an AIS 3 radius fracture versus 1.4% for an AIS 2 vault fracture.Conclusions: Trauma severity metrics are important for outcome prediction models and can be used in pediatric triage algorithms and other injury research. Trauma severity may vary for similar injuries based upon developmental stage, and this difference should be reflected in severity metrics. The MR-based data-driven determination of injury severity in pediatric occupants of different age cohorts provides a supplement or an alternative to AIS severity classification for pediatric occupants in MVCs.

Lumbar Bone Mineral Density Phantomless Computed Tomography Measurements and Correlation with Age and Fracture Incidence

Objective: Low bone quality is a contributing factor to motor vehicle crash (MVC) injury. Quantification of occupant bone mineral density (BMD) is important from an injury causation standpoint. The first aim of this study was to validate a technique for measuring lumbar volumetric BMD (vBMD) from phantomless computed tomography (CT) scans. The second aim was to apply the validated phantomless technique to quantify lumbar vBMD in Crash Injury Research and Engineering Network (CIREN) occupants for correlation with age, fracture incidence, and osteopenia/osteoporosis diagnoses.Methods: Quantitative CT (qCT) and dual-energy X-ray absorptiometry (DXA) were collected prospectively for 50 subjects and used to validate a technique to measure vBMD from 281 phantomless CT scans of CIREN occupants. Hounsfield unit (HU) measurements were collected from the L1–L5 vertebrae, right psoas major muscle, and anterior subcutaneous fat for all subjects and from 3 phantom ports with known mg/cc calcium hydroxyapatite values for the validation group. qCT calibration was accomplished using regressions between the phantom HU and mg/cc values to convert L1–L5 HU values to mg/cc. A phantomless calibration technique was developed where the fat and muscle HU values were linearly regressed against fat (−69 mg/cc) and muscle (77 mg/cc) to establish a conversion for L1–L5 HU measurements to mg/cc. vBMD calculated from qCT versus the phantomless method was compared for the 50 subjects to assess agreement and a mg/cc osteopenia threshold was established using DXA T-scores. CIREN HU measurements were converted to mg/cc using the phantomless technique and the mg/cc osteopenia threshold was used to compare vBMD to age, fracture incidence, and osteopenia comorbidity classifications in CIREN.Results: Linear regression of lumbar vBMD derived from the qCT versus phantomless calibrations showed excellent agreement (R2 = 0.87, P <.0001). A 145 mg/cc threshold for osteopenia was established (sensitivity = 1, specificity = 0.57) and 44 CIREN occupants had vBMD below this threshold. Of these 44 occupants, 64% were not classified as osteopenic in CIREN, but vBMD suggested undiagnosed osteopenia. Age was negatively correlated with vBMD in both sexes (P <.0001) and CIREN occupants with less than 145 mg/cc vBMD sustained an average 1.7 additional rib/sternum fractures (P =.036).Conclusions: Because lumbar vBMD was estimated from phantomless CT scans with accuracy similar to qCT, the phantomless technique can be broadly applied to both prospectively and retrospectively assess patient bone quality for research and clinical studies related to MVCs, falls, and aging.

Driver Injury Risk Variability in Finite Element Reconstructions of Crash Injury Research and Engineering Network (CIREN) Frontal Motor Vehicle Crashes

Objective: A 3-phase real-world motor vehicle crash (MVC) reconstruction method was developed to analyze injury variability as a function of precrash occupant position for 2 full-frontal Crash Injury Research and Engineering Network (CIREN) cases.Method: Phase I: A finite element (FE) simplified vehicle model (SVM) was developed and tuned to mimic the frontal crash characteristics of the CIREN case vehicle (Camry or Cobalt) using frontal New Car Assessment Program (NCAP) crash test data. Phase II: The Toyota HUman Model for Safety (THUMS) v4.01 was positioned in 120 precrash configurations per case within the SVM. Five occupant positioning variables were varied using a Latin hypercube design of experiments: seat track position, seat back angle, D-ring height, steering column angle, and steering column telescoping position. An additional baseline simulation was performed that aimed to match the precrash occupant position documented in CIREN for each case. Phase III: FE simulations were then performed using kinematic boundary conditions from each vehicle's event data recorder (EDR). HIC15, combined thoracic index (CTI), femur forces, and strain-based injury metrics in the lung and lumbar vertebrae were evaluated to predict injury.Results: Tuning the SVM to specific vehicle models resulted in close matches between simulated and test injury metric data, allowing the tuned SVM to be used in each case reconstruction with EDR-derived boundary conditions. Simulations with the most rearward seats and reclined seat backs had the greatest HIC15, head injury risk, CTI, and chest injury risk. Calculated injury risks for the head, chest, and femur closely correlated to the CIREN occupant injury patterns. CTI in the Camry case yielded a 54% probability of Abbreviated Injury Scale (AIS) 2+ chest injury in the baseline case simulation and ranged from 34 to 88% (mean = 61%) risk in the least and most dangerous occupant positions. The greater than 50% probability was consistent with the case occupant's AIS 2 hemomediastinum. Stress-based metrics were used to predict injury to the lower leg of the Camry case occupant. The regional-level injury metrics evaluated for the Cobalt case occupant indicated a low risk of injury; however, strain-based injury metrics better predicted pulmonary contusion. Approximately 49% of the Cobalt occupant's left lung was contused, though the baseline simulation predicted 40.5% of the lung to be injured.Conclusions: A method to compute injury metrics and risks as functions of precrash occupant position was developed and applied to 2 CIREN MVC FE reconstructions. The reconstruction process allows for quantification of the sensitivity and uncertainty of the injury risk predictions based on occupant position to further understand important factors that lead to more severe MVC injuries.

A95 The impact of declining gasoline prices on motor vehicle fatalities and injuries in seven OECD countries

Abstract Background Prior research has suggested that rising gasoline prices decreases vehicle miles traveled and thus motor vehicle crash injuries. However, gasoline prices have recently decreased and this may result in a reversal of historical declines in injuries and fatalities on public roadways. We use motor vehicle crash and gasoline price data for Belgium, France, Germany, Italy, United Kingdom (UK), United States (US) and the Netherlands to examine the historical relationship between gasoline prices and traffic safety and predict the impact of decreasing prices on fatalities and injuries in 2015. Methods Road safety data come from Organization for Economic Co-operation and Development (OECD) statistics, and gasoline price data were retrieved from the US Energy Information Administration. Outcomes are number of motor vehicle crash fatalities and injuries per million population, and the main predictor is gasoline price in US dollars per gallon, which were adjusted for inflation and for Purchasing Power Parity across countries. Random-effects models were used to estimate the effects of increasing gasoline prices on fatal and non-fatal injuries. Results Average gasoline prices varied substantially across the OECD countries in 1996-2012, ranging from $2.66 in the US to $5.71 in the Netherlands. Similarly, the number of motor vehicle crash fatal and nonfatal injuries ranged from 9,706 per million population in the US to 679 per million in the Netherlands. For all countries, the correlation between annual crash injuries and gasoline prices was significant and negative. Overall, the correlation between prices and all injuries per million population was -.59. Multivariate log regression analysis, adjusting for GDP per capita, unemployment rates, percent urban population and random effects, predicts that a 10% decrease in gasoline prices results in a 3.0% increase in non-fatal injuries and 8.5% increase in fatal injuries per million population. Compared to 2012, gasoline prices in January 2015 are an average of 26.8% lower across all countries. Our multivariate analysis suggests that this is predicted to result in 8.0% more non-fatal injuries and 23% more fatal injuries. For example, the UK is predicted to have an increase of 385 fatalities and 15,460 injuries if recent decreases in gasoline prices persist into the future. Conclusions Our findings suggest that declining gasoline prices may result in an increase in fatal and non-fatal injuries from motor vehicle crashes in several OECD countries. This may potentially slow or reverse the historical decline in motor vehicle injuries over the prior decade.

P13 An international comparison of mobile phone subscribership and motor vehicle crash injuries

BackgroundMobile phone use while driving has been associated with a substantially higher likelihood of motor vehicle crash risk and is the focus of numerous traffic safety policies and initiatives worldwide in recent years. Although prior studies have examined the relationship of distracted driving and crash risk using national data, few if any studies have explored cross-national differences in mobile phone use on motor vehicle crash rates. We use longitudinal data for 23 countries to examine the association between rates of mobile phone subscribership and injuries and fatalities on public roadways. MethodsRoad safety data are reported by the Organization for Economic Co-operation and Development (OECD). We examine 23 OECD countries for the 11-year period, 2001–2011. Generalized least squares (GLS) regression is used to examine logged nonfatal injuries and fatalities per 100,000 population with the log number of mobile phone subscribers per 100 people, adjusting for number of motor vehicles (cars, buses, other), percent urban population, unemployment rate, GDP per capita, year and country fixed effects. ResultsFrom 2001 to 2011, countries experienced a 23.3% decline in rates of motor vehicle injuries—decreasing from 394.2 to 302.5 per 100,000 population. However, trends in motor vehicle crash injuries varied across countries. For example, Denmark and France experienced a more than 50% decrease in injury rates since 2001, but rates in Australia increased 4.4%, from 151.6 to 158.3 per 100,000 population. Mobile phone subscribership increased substantially in this period, but rates and growth also varied significantly across countries. For example, in Switzerland, an average of 10 persons per 100 have a mobile phone; this compares to 77.2 in Great Britain. Growth rates in subscribership ranged from 22.3% in Iceland to nearly 200% in Estonia and Turkey in the study period. GLS regression analysis suggests a significant and positive association between rates of mobile phone subscribership and motor vehicle crash injuries. A 10% increase in subscribers per 100 people is predicted to result in an increase of 12.0% (p<.001) and 7.5% (p<.001) in crash injuries and fatalities per 100,000 people, respectively. ConclusionsWe present evidence that increasing rates of mobile phone subscribership may be associated with motor vehicle crash injuries. Distracted driving is a problem worldwide and, thus, more cross-national efforts are needed to identify best practices in policy implementation to help address this problem.

P06 Varied Severity of Motor Vehicle Crash Injuries Using National Dataset in Taiwan

BackgroundInjuries by motor vehicle crashes remain the priority concern in the public-health. The aims of this study were to determine the distribution of varied severity of motor vehicle crash (MVC) injuries, and the time trend of MVC injuries by different car type between 2003 and 2010 in Taiwan. MethodsPooled data from Taiwan׳s National Traffic Accident Dataset, Taiwan׳s National Health Insurance Database, and National Register of Deaths for the year 2003 through 2010 were used. A total of 2,405,674 subjects involved in MVC events were included. The severity of MVC injuries were classified as emergency-visit only (ER-visit), hospitalization and death. Frequency counts, percentages and 95% confident interval were estimated for descriptive analyses. Mann-Kendall test was used to determine time trend of varied severity injuries by car types. ResultsIn 2010, the percentages of MVC subjects who were injured with ER-visit only, hospitalization, or death were 33.9%, 6.9% and 0.6% respectively. Vulnerable road users as cyclists and motorcyclists had highest probability of sever injury outcomes due to MVC rather than all other types of vehicle drivers. Compared with sedan drivers, cyclist had approximately 10 times more risk of ER-visit, 15 times more risk of hospitalization, 9 times more risk of death in MVC. Among motorcyclists, the risks of getting ER-visit, hospitalization, or death were 9, 11, 4 times higher than sedan drivers in MVC respectively. Over the period 2003 to 2010, the results of time trend test showed that the percentage of hospitalization or death among drivers of MVC had significantly decreased with years, however, the ER-visit utilization increased from 26.2% in 2003 to 34.0% in 2010. After stratification of car types, the ER-visit utilization among cyclist and motorcyclist of MVC remains significantly increased by years. ConclusionsThe evidences presented that the severity of MVC occurred from cyclists and motorcyclists is the major problems of motor vehicle crashes in Taiwan. Therefore, governments and health care providers to address on motorists and cyclist safety education, and to allocate an appropriate level of medical resources in order to effectively deal with different injury severity patterns.

Restriction in functioning and quality of life is common in people 2months after compensable motor vehicle crashes: prospective cohort study.

BackgroundWe sought to identify the role of pre-injury socio-demographic and health characteristics, and injury severity in determining health-related quality-of-life outcomes for mild to moderate injuries 2 months after a motor vehicle crash in a compensable setting.MethodsPeople aged 17 years and older, injured with a New Injury Severity Score of 8 or less, in a motor vehicle crash in New South Wales and who had registered a claim with the Compulsory Third Party Insurance scheme from March to December 2010 were contacted to participate in the study. Information for 364 eligible participants was primarily collected through telephone interview, approximately 2 months after injury.ResultsSubstantial proportions of participants continued to have adverse outcomes approximately 2 months after their injury with mean Short Form Health Survey (SF-12) physical component score of 36.7 (SD ±10.3), SF-12 mental component score of 46.6 (SD ±11), Euro Qol (EQ) analogue scale score of 65.8 (SD ±18) and Euro Qol five dimension (EQ-5D) summary score of 0.70 (SD ±10). Key factors predicting adverse outcomes were prior chronic illness, obesity, hospitalisation and self-perceived threat to life due to injury.ConclusionsThis study highlights the substantial impact of apparently “minor” motor vehicle crash injuries in a compensable setting and suggests targets for studies of tertiary prevention to improve health-related quality-of-life outcomes.Electronic supplementary materialThe online version of this article (doi:10.1186/s40621-015-0042-7) contains supplementary material, which is available to authorized users.

Emergency department visits vs. fatalities among substance-impaired underage youths involved in motor vehicle crashes

IntroductionEmergency department (ED) visits resulting from motor vehicle crashes (MVCs) among individuals younger than 21 impaired by alcohol and/or drugs have been less studied than MVC fatalities. MethodUsing data from 2004 to 2011, we compare the magnitude and pattern of national ED visit and mortality data for alcohol- and drug-impaired youths involved in MVCs. ResultsTemporal patterns of ED visits are similar to those of fatalities, but the two differ in magnitude. The ratio of ED visits to fatalities is 3.5:1; alcohol related events involvement dominates other drugs in both categories. DiscussionThe volume of injuries serious enough to warrant ED visits imposes significant health, social, and financial burdens. In ED visits, alcohol is the prime source of MVC morbidity burden; other drugs consistently contribute less. Practical applicationsThese incidents are persistent and require interventions aimed at multiple levels of prevention, including stricter corrective steps earlier in the impaired driving career to reduce subsequent incidents. ED visits for MVC injuries can be important “teachable moments.” Limitations of the study indicate the need for improved surveillance of underage substance-involved crashes.