Front Seat Occupants Research Articles

Comprende Code Switching?

<h3>Background and Aims</h3> Road traffic injury (RTI) is a leading cause of death and injury in the United Arab Emirates (UAE). Mortality from RTI is higher in the UAE compared to similar countries in the world (MoH, 2018). Wearing seatbelts reduce deaths among drivers and front seat occupants by 45–50% (WHO, 2018). The enforcement and regular observation of seatbelt are essential to control deaths from RTIs. This study aims to estimate seatbelt use in Abu-Dhabi emirate, UAE. <h3>Methods</h3> A cross sectional analysis, using direct observation of drivers and front seat passengers at petrol stations in Abu Dhabi and Al Ain, the two large cities in Abu Dhabi emirate, was undertaken during January-March 2020, to assess compliance with the seatbelt law in the UAE. <h3>Results</h3> A sample size of 706 motor vehicles was approached, and the response was 87.4%. Overall, 45.5% of drivers and 50% of front seat passengers wore seatbelts. Women (55.7%) were more compliant with seatbelts compared to men (p&lt;0.04). Local citizens were less compliant with seatbelts compared to nonlocals (39.1% vis-a-vis 44.2; p&lt;0.05). <h3>Conclusions</h3> The results showed a slight improvement in seatbelts use in Abu Dhabi emirate, compared with previous estimates by Barss et al. (2008), where 10% of local citizens and 40% of nonlocal citizens were reported using seatbelts (2008). More efforts are thus needed to maintain the improvements made. The new data will help directing the public attention to increase awareness and enforcement of seatbelt use among the population in the UAE.

Injury severity of occupants in lateral collisions in standard and small vehicles: Analysis of ITARDA's in-depth investigation data

A retrospective analysis was performed to investigate the differences in occupant injury characteristics between standard and small vehicles in lateral collision. From the in-depth data of the Institute for Traffic Accident Research and Data Analysis (ITARDA) from 1993 to 2003, data were collected for 331 adults who were front-seat occupants involved in single lateral motor vehicle collisions. The accident information, the subjects’ medical data and the anatomical injury severity scores were examined. The involved passenger vehicles were classified as small or standard. Seatbelts were effective in decreasing the head–neck injury severity of far-side occupants of standard vehicles, but in small vehicles, no significant benefit was observed. In standard vehicles, far-side occupants suffered less severe injuries than near-side occupants, but this trend was not apparent in small vehicles. These differences may result from the smaller interior space of the smaller vehicles.

Disparities in Trauma Center Access of Older Injured Motor Vehicular Crash Occupants

To evaluate whether older injured motor vehicular crash (MVC) occupants' access to trauma centers (TC) reflects the lower threshold suggested in triaging recommendations. Adult front seat occupants of MVCs transported to a hospital from 1999 through 2006 included in the National Automotive Sampling System (NASS) were studied. Cases were classified by their age in years (≤60 years or >60 years). Younger and older injured MVC occupants were compared in relation to their likelihood of being transported to a TC. Multiple logistic regression models were built to adjust for confounders. A total of 35,830 cases representing 7,894,940 cases after weighting were analyzed. Older occupants were less likely to be transported to a TC than younger ones (47% vs. 55%, p < 0.0001). Older individuals were more likely to be restrained, passengers, and seated on the impacted side of lateral crashes. Injury severity was higher among the older group (mean Injury Severity Score, 4.1 vs. 3.1; p < 0.0001) and so was the resulting mortality (1.7% vs. 0.6%, p < 0.0001). Multiple logistic regression models after adjusting for confounders (i.e., other triage criteria) revealed a lower likelihood of TC transport (odds ratio, 0.75 [0.57-0.98]) for the older group. In contrast to the American College of Surgeons triaging recommendations, injured MVC occupants older than 60 years are less likely to be transported to a TC than their younger counterparts. Further studies should establish whether the lower access to TC experienced by the older population is a function of geographical factors, emergency medical services unconscious bias, or other factors.

Upper Extremity Injuries in Road Traffic Accidents

Objectives The mechanisms of upper limb injuries in road traffic accidents have not been widely investigated or understood. The present study was designed to obtain more specific information on upper limb injuries sustained by front seat occupants involved in front- and side-impact collision car accidents. Its purpose was to identify injuries that are a priority for prevention and further research. Methods Hospital records, radiographs and, where appropriate, crash data were reviewed. Data were analyzed to identify the frequency and severity of upper limb injuries, the mechanism of injury and the impairment sustained, in accordance with the American Medical Association guide. The total financial costs for NHS management, as well as that relating to the upper limb injury, were calculated. Results Sixty-two cases were reviewed (34 males), with a mean (range) age of 44 years (18 years to 83 years). There were 20 clavicle fractures of which 18 were right sided, and often attributed to a ‘seat-belt effect’. There were also 17 wrist and 13 forearm fractures. The median (range) upper limb Abbreviated Injury Score was 2 (2 to 4) and the overall Injury Severity Score was in the range 1 to 50 (median 6). In terms of impairment, the upper extremity sensory deficit was in the range 0% to 9% and motor deficit 0% to 22.5%, giving up to 5% sensory and 13.5% motor ‘whole person impairment’. The mean treatment cost for upper limb management was £2200 compared to a mean total injury treatment cost of £11,000 per person. Discussion The present study has served to identify the range and subsequent costs (impairment and financial) of upper limb injuries in road traffic accidents. These data will be used by researchers to advance the design of current and future car crash dummies in the upper limb and to allow accurate finite element remodelling. These data may be used in support of legislative changes in the future.

Upper Extremity Injuries in Restrained Front-Seat Occupants After Motor Vehicle Crashes

Prior studies identified that crash severity (delta V), occupant position, and restraint systems as reliable predictors of crash injuries to lower extremity, but very little have been written on the subject of upper extremity. This is a retrospective analysis of Crash Injury Research and Engineering Network database in a Level I trauma center focusing on severe upper extremity injuries. The aim was to investigate the relationship between types of the "crash" and "occupant" factors on the pattern and severity of upper extremity injuries after a frontal collision. Majority of the injuries were soft tissues nature (67.6% soft tissue vs. 32.4% fractures). There were 144 fractures to the upper extremity, 12.5% were "open" fractures; 74.5% of the fractures sustained in the upper extremity occurred distal to the elbow, whereas soft tissue injuries predominated in the humerus. Also noted that occupants who sustained fractures were on average 6.7 kg lighter than those who sustained soft tissue injuries (84.5 kg soft tissue vs. 77.86 kg fracture, p < 0.05). We postulate that there may be a protective effect of "soft tissue cushion" toward protecting the content from serious harm, in this case the humerus. Instrument panel, airbag, and seat belts were the main injury source. After adjusting for other modifiers, occupants who sustained fractures had a significantly higher Injury Severity Scores (mean Injury Severity Scores 21.88 vs. 17.68, p < 0.05). This implied that those who sustained fractures to upper extremity most likely had associated significant injuries to other body region, necessitating further medical attention. Further improvement in vehicle safety performance in the form of "depowered" airbag and efficient energy absorbing material within the vehicle interior is warranted.

Evaluation of the Click It or Ticket intervention in Utah

Objective To evaluate the Click It or Ticket (CIOT) intervention conducted in Utah by comparing changes in safety belt use using observational safety belt surveys pre- and post-intervention. Methods Observational surveys of safety belt use for drivers and front seat passengers (collectively referred to as front seat occupants) were conducted before and after the media and enforcement blitz of the CIOT intervention. Data were collected from 16 urban sites during the daytime and nighttime. Logistic regression and generalized estimating equations were used to compute odds ratios for safety belt use adjusted for front seat occupant characteristics. Results Overall safety belt use was observed at 76.5% pre-intervention and 84.8% post-intervention, an improvement of 8.3% (95% confidence interval [CI]: 5.2%, 11.3%). Daytime and nighttime safety belt use improved by 7.8% (95% CI: 3.5%, 12.1%) and 9.7% (95% CI: 6.4%, 13.0%), respectively. While males showed a greater improvement (9.9%) in safety belt use when compared to females (5.7%); males were still less likely to use safety belts than females. Conclusions The CIOT intervention is associated with increased safety belt use at the sites observed in Utah, including among the two high risk groups targeted by the intervention: nighttime occupants and males.

A matched-cohort analysis of belted front and rear seat occupants in newer and older model vehicles shows that gains in front occupant safety have outpaced gains for rear seat occupants

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.

Severe-to-Fatal Injury Risks in Crashes With Two Front-Seat Occupants by Seat Belt Use

Purpose: This study investigates the risk of severe-to-fatal injury (Maximum Abbreviated Injury Score, MAIS 4+F) in crashes with two front-seat occupants. It determines the relative risk of injury in the same crash by belt use and seating position. Methods: 1993–2008 NASS-CDS was analyzed for crashes with occupants in both front-outboard seats. The effect of belt use was investigated for the driver and passenger. Light vehicles were included with model year 1990+. Injury severity was subdivided into MAIS 0–2 and 4+F in NASS-CDS to compare no-to-moderate injury with severe-to-fatal injury. Standard errors were calculated in SAS and the z-test was used to determine the significance of differences in risk. Relative risks were determined by seat belt use and seating position; odds ratios were determined for one or both occupants being severely injured. Results: In 76.7 percent of the MAIS 4+F crashes, either the driver (32.4%) or passenger (44.3%) was severely injured, rather than both occupants (23.3%). When both were belted, one occupant was severely injured in 86.5 percent of crashes. When both were unbelted, both occupants were severely injured in 68.9 percent of the crashes. Both occupants were belted in 74.7 percent of the cases and unbelted in 18.6 percent. In 6.7 percent of crashes, either the driver (4.4%) or passenger (2.3%) was unbelted when the other was belted. The highest risk occurred with an unbelted driver and belted passenger (4.98 ± 0.73% vs. 1.97 ± 0.38%, z = 3.65, p < .05). When both occupants were belted, the driver and passenger injury risk was similar (0.459 ± 0.098% vs. 0.449 ± 0.047%, z = 0.10, ns). Conclusions: In crashes with two front occupants, typically one occupant was severely injured, not both. Overall, the odds ratio was 3.28 for one compared to two occupants being severely injured; and, risks vary by seat belt use and seating position. The highest relative risk for unbelted versus belted occupants was 9.22 when both occupants were severely injured in the same crash.

Describing a Problem: Rear Seatback Failure and Unsecured Cargo

Currently, there is little in the literature regarding the ability of rear seatbacks to act as a protective barrier from cargo in frontal crashes. However, it has been shown that unrestrained rear passengers pose a danger to front seat occupants. The association of rear seatback failures and intrusions with mortality and serious injury were examined. The Seattle CIREN database for restrained, rear-seat passengers in front-end crashes with seatback failure or intrusion was searched. Injury patterns and crash characteristics, including the role of unrestrained cargo were examined. Next, the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) database was queried for restrained rear-seat passengers in front-end crashes with recorded seat failure or intrusion. Mortality, maximum Abbreviated Injury Scale (AIS) score and mean Injury Severity Scale (ISS) scores were compared with passengers who had no failure or intrusion. Linear regression was used to identify the differences between the groups. Logistic regression was used to estimate the mortality risk associated with seat failure. There were four CIREN cases that met the criteria. In each case, the occupant suffered significant injury or death. All four of the seat failures were the result of unrestrained cargo striking the seatback. The CDS data revealed a statistically significantly increased mortality (OR = 18.9, 95% CI = 14.0-25.7) associated with seat failure. Both the maximum AIS and mean of the ISS scores were higher in the failure/intrusion group (p <0.0001). Rear seatback failure/intrusion is associated with increased mortality and injury. Case reports suggest unrestrained cargo plays a significant role in these injuries.

Front Air Bag Nondeployments in Frontal Crashes Fatal to Drivers or Right-Front Passengers

Objective : Public concern has arisen about the reliability of front air bags because Fatality Analysis Reporting System (FARS) data indicate many nondeployed air bags in fatal frontal crashes. However, the accuracy of air bag deployment, the variable in question, is uncertain. This study aimed to provide more certain estimates of nondeployment incidence in fatal frontal crashes. Methods : Fatally injured passenger vehicle drivers and right-front passengers in frontal crashes were identified in two U.S. databases for calendar years 1998–2006 and model years 1994–2006: FARS, a census of police-reported fatal crashes on public roads, and National Automotive Sampling System/Crashworthiness Data System (NASS/CDS), a probability sample of tow-away crashes. NASS/CDS contains subsets of fatal crashes in FARS and collects detailed data using crash investigators. Front air bag deployment coding for front-seat occupant fatalities was compared in FARS and NASS/CDS, and case reviews were conducted. Results : Among FARS frontal deaths with available deployment status (N = 43,169), front air bags were coded as not deployed for 18 percent of front occupants. In comparison, NASS/CDS (N = 628) reported 9 percent (weighted estimate) nondeployment among front occupants killed. Among crashes common to both databases, NASS/CDS reported deployments for 45 percent of front occupant deaths for which FARS had coded nondeployments. Detailed case reviews of NASS/CDS crashes indicated highly accurate coding for deployment status. Based on this case review, 8 percent (weighted estimate) of front occupant deaths in frontal crashes appeared to involve air bag nondeployments; 1–2 percent of front occupant deaths represented potential system failures where deployments would have been expected. Air bag deployments appeared unwarranted in most nondeployments based on crash characteristics. Discussion : FARS data overstate the magnitude of the problem of air bag deployment failures; steps should be taken to improve coding. There are inherent uncertainties in judgments about whether or not air bags would be expected to deploy in some crashes. Continued monitoring of air bag performance is warranted.

Severe Injury to Near- and Far-Seated Occupants in Side Impacts by Crash Severity and Belt Use

Purpose: This study investigated the risk of severe-to-fatal injury (MAIS 4+F) to near- and far-seated front occupants in side impacts by belt use and crash severity (delta V). Methods: 1993–2007 NASS-CDS was analyzed for front-seat occupants in side impacts while they were either the near-side or far-side occupant by belt use. Light vehicles were included with model year 1994+. Injury severity was subdivided into MAIS 0–2, 3, and 4+F. The risk for MAIS 4+F injury was determined by dividing the number of MAIS 4+F by the number of exposed occupants with known injuries. Individual NASS-CDS cases were downloaded from the 1997–2007 electronic data to evaluate injury patterns causing high relative risks. Results: In 35+ mph side-impact delta Vs, the risk for MAIS 4+F injury was 75.4 ± 41.0% for unbelted near-side and 48.1 ± 14.6% for unbelted far-side occupants. The risk was 51.8 ± 14.8% for belted near-side and 30.9 ± 8.2% for far-side occupants. Seat belt use was 81.4% effective in preventing MAIS 4+F injury for near-side occupants and 93.5% for far-side occupants. The relative risk (RR) for unbelted compared to belted occupants was 35.9 for far-side occupants in 10–15 mph delta V crashes. The relative risk was 35.1 for near-side occupants in < 10 mph delta V side impacts. The high relative risks were associated with complex, high-speed multi-collision crashes often with occupant impacts on the windshield, steering wheel, or other frontal components and ejection. Conclusions: Seat belt use was more effective in preventing severe injury (MAIS 4+F) to far-side occupants than near-side occupants in < 25 mph delta V impacts. High relative risk for unbelted occupants in low-speed side impacts was explained by the fact that the accidents were high-speed, multi-impact collisions. Severe injury was caused by ejection, impact with the side interior, or impact with the frontal components where airbags sometimes deployed.

The Effect of Air Bags on Pregnancy Outcomes in Washington State

To estimate whether air-bag deployment is associated with an increased risk of adverse pregnancy outcomes. We performed a retrospective cohort study to assess the effect of air-bag availability and air-bag deployment on the risk of adverse pregnancy outcomes among pregnant, front-seat occupants in motor vehicle crashes in Washington State. Pregnant women involved in motor vehicle crashes were identified by linking birth and fetal death certificate data with Washington State Patrol crash data, which reported air-bag availability and deployment. We calculated relative risks (RRs) of adverse maternal and perinatal outcomes and 95% confidence intervals (CIs) using Poisson regression, adjusted for maternal age, seatbelt use, and vehicle model year. We found no increased risk of adverse maternal or perinatal pregnancy outcomes among occupants of air-bag-equipped vehicles in all collisions (n=2,207) compared with those in vehicles without air bags (n=1,141). Among crashes in which air-bag deployment would be likely, we found a nonsignificant 70% increased risk of preterm labor (RR 1.7, 95% CI 0.9-3.2) and a nonsignificant threefold increased risk (RR 3.1, 95% CI 0.4-22.1) of fetal death among occupants in vehicles with air-bag deployment compared with occupants in vehicles without air bags, although fetal death results were limited by small numbers (2/198 [1.0%] in pregnant women whose air bags deployed; 2/622 [0.3%] in pregnant women whose air bags did not deploy). Our findings provide clinicians with evidence to advise women that air bags do not seem to elevate risk of most potential adverse outcomes during pregnancy. II.

Vehicle Model Year and Crash Outcomes: A CIREN Study

Objective: To quantify the effect of model year (MY) on the occurrence of severe injuries and death after involvement in motor vehicle crashes. Methods: Cases involving adult front seat occupants of vehicles MY ≥ 1994 equipped with frontal airbags were selected from the Crash Injury Research and Engineering Network (CIREN) database. Cases were grouped by MY: 1994–1997, 1998–2004, and 2005–2007 (MY groups [MYG] 1, 2, and 3, respectively. MYGs were compared in relation to mortality, Injury Severity Score (ISS), and the occurrence of Abbreviated Injury Severity score (AIS) 3+ and AIS4+ injuries to each body region using Mantel Haenszel chi-square, Kruskal-Wallis, and Bonferroni corrected t test. To adjust for confounders, multiple logistic regression models were built to explore the association of MYG with death. Covariates included age, BMI, delta v, principal direction of force (PDOF), restraint use, and vehicle type. Results: A total of 1888 cases was distributed within MYG1 (34%), MYG2 (62%), and MYG (34%). Age, gender, BMI, and PDOF distribution did not differ among MYGs. Though ISS distribution was not different, a decrease in the occurrence of AIS4+ of the thorax and spine regions was noted over time. Mortality also decreased over time (18, 9, and 4% MYG 1, 2, and 3, respectively). Multivariate analysis revealed a protective effect of MYG2 and MGY3 (odds ratio [OR], 0.57 [0.44–0.75] and 0.22 [0.07–0.50], respectively) in relation to death. Conclusions: Front seat occupants of later MY vehicles injured during crashes experience a decreased likelihood of very severe thoracic injuries, spinal injuries, and death.

Rear-Seat Motor Vehicle Travel in the U.S.: Using National Data to Define a Population at Risk

Recent studies suggest that the relative protection offered by rear seating in motor vehicle crashes has decreased, potentially reflecting disproportionate advancements in front-seat safety technology. Safe adaptation of advanced front-seat restraint systems for the rear-seat environment will require exposure data that are currently unavailable. This study uses national data to quantify rear-seat occupancy patterns, restraint use, and annual travel exposure in the U.S. in order to support the development of advanced crash protection systems for rear-seat motor vehicle occupants. Data from the 2000-2006 National Automotive Sampling System Crashworthiness Data System and 2001 National Household Transportation Survey were analyzed in 2008 to quantify occupancy patterns (e.g., seat position, restraint use) and annual person-trips for rear-seat passengers in the U.S. The overall proportion of person-trips by rear-seat occupants is relatively low (12.9%); however national at-risk exposure remains significant (approximately 39 billion annual person-trips). Annual rear-seat travel exposure is similar among children < or = 12 years and adults (18.9 vs 19.1 billion person-trips) despite the fact that children are proportionally much more likely to ride in rear positions (79.3% vs 7.4%). Restraint use among adult rear-seat occupants was also much lower than among front-seat occupants (50.4% vs 82.2%). While rear-seat occupancy is relatively low compared with front-seat occupancy at-risk rear-seat travel by both child and adult passengers in the U.S. remains significant. Restraint use by rear-seat occupants is much lower than that among front-seat passengers, particularly among adults and older children, substantially increasing injury risk. Development of future crash protection systems for rear-seat passengers must account for these exposure patterns to ensure safe and effective integration into production vehicles.

Thoracolumbar junction injuries after rollover crashes: difference between belted and unbelted front seat occupants

Motor vehicle collision (MVC) is one of the most common causes of thoracolumbar junction (TLJ) injury. Although it is of no doubt that the use of seatbelt reduces the incidence and severity of MVC-induced TLJ injury, how it is protective for front-seat occupants of an automobile after rollover crashes is unclear. Among 200 consecutive patients with a major TLJ (Th11-L2) injury due to high-energy trauma admitted from 2000 to 2004, 22 patients were identified as front-seat occupants of a four-wheel vehicle when a rollover crash occurred. The 22 patients were divided into two groups: 10 who were belted, and 12 who were unbelted. Patients' demographics including the mean Injury Severity Score (ISS), incidence of neurologic deficit, level of TLJ injury, and type of TLJ injury according to the AO fracture classification were compared between the two groups. Neurologic deficit was present exclusively in the unbelted group, and the difference in the incidence was statistically significant (P = 0.04). Similarly, AO type B/C injury was present exclusively in the unbelted group. The belted group had a significantly lower mean ISS than the unbelted group (P < 0.01). Comparison between the ejected and non-ejected victims within the unbelted group revealed no statistical difference in the incidence of neurologic deficit or type of injury. It is likely that the high incidence of neurologic deficit in the unbelted group was due to the high incidence of AO type B/C injury. This study indirectly proves the efficacy of seatbelt in reducing the severity of rollover-induced TLJ injury. Because of the limited number of cases, it is uncertain whether ejection from vehicle, which occurs exclusively in the unbelted victims, is a crucial factor in determining the severity or type of injury after rollover crashes.

Injury patterns in frontal crashes: The association between knee–thigh–hip (KTH) and serious intra-abdominal injury

Safety belts protect occupants in frontal impacts by reducing occupant deceleration and preventing the occupant from hitting interior vehicle components likely to cause injury. However, occupants moving forward during the impact may contact the safety belt webbing across their chest and abdomen. We hypothesized that if the occupant loaded their knee–thigh–hip (KTH) region with enough force to result in injury to this region—it might prevent compression (and injury) of their abdomen by the safety belt. Crash Injury Research and Engineering Network (CIREN) data were used to test the association between KTH and intra-abdominal injury related to safety belts. Odds ratios with 95% confidence limits (CL) and logistic regression models were used to assess statistical significance. Analyses were based on 706 CIREN adult, front seat occupants using their safety belt and injured in frontal crashes. Occupants with KTH injury were four times less likely (adjusted odds ratio = 0.25, 95% CL 0.10, 0.62) to have concomitant serious intra-abdominal injury caused by the safety belt. Although safety belts save lives and prevent serious injury, some occupants may sustain serious intra-abdominal injury when the abdomen is loaded by the safety belt during a frontal impact. These results may be useful to motor vehicle manufacturers and others who design and test motor vehicle safety systems.

Front versus Rear Seat Injury Risk for Child Passengers: Evaluation of Newer Model Year Vehicles

Objective: Design improvements to frontal air bags for vehicles of model year 1998 and newer have reduced the risk of injury to child occupants exposed to their deployment. These changes in conjunction with other improvements in the protection of front seat occupants give impetus for the reconsideration of rear seating recommendations for child occupants. Thus, the objective of this study was to evaluate the association between seating row (front vs. rear) and risk of injury to children in newer model year vehicles. Methods: Data was collected on child occupants from December 1, 1998, to November 30, 2007, via insurance claim records and a validated telephone survey. The study sample included child occupants aged 0 to 15 years seated in the front and rear rows of vehicles model year 1998 or newer, involved in a crash in sixteen states. Children were classified as injured if a parent or driver reported an injury corresponding with Abbreviated Injury Scale scores of ≥2. The age-specific relative risk of injury by seat row was calculated for the whole data set and then further stratified by model year. Results: Complete interview data were obtained on 10,670 crashes involving 16,920 children, representing an estimated 205,408 crashes with 314,968 child passengers in the study population. The adjusted relative risk of injury to children in the rear seat compared to those in the front was 0.36 (0.23–0.57) and 0.69 (0.49–0.98) for 0- to 8-year-olds and 9- to 12-year-olds, respectively. For 13- to 15-year-olds, the reduced injury risk associated with rear row seating narrowly missed statistical significance. When stratified by model year (1998 to 2002 and 2003+), all age group/model year combinations demonstrated a crude rear row injury risk that was lower than that of the front row. Conclusions: This analysis, conducted on a set of vehicles with advanced front seat safety systems including second-generation and newer air bags, strongly confirmed the recommendation that all children 0–12 years should be seated in the rear row(s) of their vehicles. Children in the rear row(s) were one half to two thirds as likely to sustain injury than those in the front after adjusting for potentially confounding crash, vehicle, and child factors.

Real-Life Fatal Outcome in Car-to-Car Near-Side Impacts—Implications for Improved Protection Considering Age and Crash Severity

Objective: Recent studies have shown that current side airbags, protecting head and chest, are saving lives in near-side impacts (Kahane 2007; McCartt and Kyrychenko 2007). The aim of this study was to analyze NASS/CDS real-life data on fatal trauma in near-side car-to-car crashes, stratified by age into non-senior and senior occupants. Furthermore, a hypothetical model explaining side airbag effectiveness as a function of lateral delta-v was presented. The model together with the field data was then used to demonstrate further enhancement of side airbag restraint performance. Method: Weighted NASS/CDS data from 1994 to 2006 for front seat occupants in near-side car-to-car impacts was used to calculate the exposure, incidence, and risk of fatal trauma with respect to lateral delta-v. The dataset was also divided into non-senior (10–59 years) and senior (age ≥ 60 years) occupants. The hypothetical model was created to adjust the NASS/CDS data to represent a car fleet fully equipped with current side airbag protection. The model was then used to evaluate the increase in effectiveness of improved side airbag protection achieved by increasing the lateral delta-v in the range where the airbag have most mitigating effect, increasing the airbag protection level within the delta-v range currently tested, and a combination of the two approaches. Results: From the NASS/CDS data, the median delta-v for fatal injury was 37 km/h for the total sample. When stratified with respect to age, the median delta-v for fatal injury was 41 km/h for non-seniors and 28 km/h for senior occupants. The exposures for both age groups were similar. However, the fatal incidence showed a difference in delta-v range between non-senior and senior occupants. Applying the airbag model increased the median delta-v to 40 km/h for the total sample and 47 and 30 km/h for non-seniors and seniors, respectively. Conclusions: Current side airbag systems offer very good protection for non-senior occupants up to delta-v 40 km/h. Though still high, the protection for senior occupants is lower. To enhance side airbag protection, the side airbag performance should be maximized where the fatal incidence is high. Therefore, to further reduce non-senior fatalities, the test speed should be increased. To further reduce senior fatalities, the protection level within severities currently tested should be increased. A combination of the two approaches would result in about a 40 percent increase of the side airbag effectiveness.

Traumatic Brain Injury After Frontal Crashes: Relationship With Body Mass Index

Previous studies had demonstrated that injury severity and risk of death after motor-vehicle crashes are related to human body characteristics. The purpose of this study was to clarify the relationship between body mass index (BMI) and head injury severity in front seat passengers after a frontal collision. Data from all front seat occupants with at least one injury, older than 16 years old involved in a frontal collision from 1993 to 2005 were retrieved from the National Automotive Sampling System (NASS) database. Patient and collision characteristics were analyzed. Two cohorts were defined according to BMI < or > or =30 kg/m2. A total of 6,977 patients were included in this study, 5,918 (85%) had complete data on weight and height. Patient's mean age was 37 +/- 18 years old, the median ISS was 6, interquartile range (IQR) 15, and 61% were men. The mortality rate was positively associated to the crash delta velocity (DV) (p < 0.0001). The use of restraint system reduced the risk of death (p = 0.01). There was a significant increase in fatal outcome (p < 0.0001; RR 1.84 95% CI 1.61-2.1) and injury severity (ISS >25 p < 0.0001; RR 1.36 95% CI 1.19-1.54) in the obese cohort. Obese patients had higher chances of having a maximum head injury (Abbreviated Injury Score head = 6) than those not obese (p = 0.003; RR 1.97 95% CI 1.52-2.55). Obese passengers are more likely to suffer a more severe head trauma after a frontal collision. Further studies with computational models are needed to determine the precise role of BMI on brain injury-related biomechanical metrics.

Association of Contact Loading in Diffuse Axonal Injuries From Motor Vehicle Crashes

Although studies have been conducted to analyze brain injuries from motor vehicle crashes, the association of head contact has not been fully established. This study examined the association in occupants sustaining diffuse axonal injuries (DAIs). The 1997 to 2006 motor vehicle Crash Injury Research Engineering Network database was used. All crash modes and all changes in velocity were included; ejections and rollovers were excluded; injuries to front and rear seat occupants with and without restraint use were considered. DAI were coded in the database using Abbreviated Injury Scale 1990. Loss of consciousness was included and head contact was based on medical- and crash-related data. Sixty-seven occupants with varying ages were coded with DAI. Forty-one adult occupants (mean, 33 years of age, 171-cm tall, 71-kg weight; 30 drivers, 11 passengers) were analyzed. Mean change in velocity was 41.2 km/h and Glasgow Coma Scale score was 4. There were 33 lateral, 6 frontal, and 2 rear crashes with 32 survivors and 9 were fatalities. Two occupants in the same crash did not sustain DAI. Although skull fractures and scalp injuries occurred in some impacts, head contact was identified in all frontal, rear, and far side, and all but one nearside crashes. Using a large sample size of occupants sustaining DAI in 1991 to 2006 model year vehicles, DAI occurred more frequently in side than frontal crashes, is most commonly associated with impact load transfer, and is not always accompanied by skull fractures. The association of head contact in >95% of cases underscores the importance of evaluating crash-related variables and medical information for trauma analysis. It would be prudent to include contact loading in addition to angular kinematics in the analysis and characterization of DAI.