An energy-absorbing sliding seat for reducing neck injury risks in rear impact—analysis for prototype built

Objective: This study investigated overall performance of an energy-absorbing sliding seat concept for whiplash neck injury prevention. The sliding seat allows its seat pan to slide backward for some distance under certain restraint force to absorb crash energy in rear impacts.

Methods: A numerical model that consisted of vehicle interior, seat, seat belt, and BioRID II dummy was built in MADYMO to evaluate whiplash neck injury in rear impact. A parametric study of the effects of sliding seat parameters, including position and cushion stiffness of head restraint, seatback cushion stiffness, recliner characteristics, and especially sliding energy-absorbing (EA) restraint force, on neck injury criteria was conducted in order to compare the effectiveness of the sliding seat concept with that of other existing anti-whiplash mechanisms. Optimal sliding seat design configurations in rear crashes of different severities were obtained. A sliding seat prototype with bending of a steel strip as an EA mechanism was fabricated and tested in a sled test environment to validate the concept. The performance of the sliding seat under frontal and rollover impacts was checked to make sure the sliding mechanism did not result in any negative effects.

Results: The protective effect of the sliding seat with EA restraint force is comparable to that of head restraint–based and recliner stiffness–based anti-whiplash mechanisms. EA restraint force levels of 3 kN in rear impacts of low and medium severities and 6 kN in impacts of high severity were obtained from optimization. In frontal collision and rollover, compared to the nonsliding seat, the sliding seat does not result in any negative effects on occupant protection. The sled test results of the sliding seat prototype have shown the effectiveness of the concept for reducing neck injury risks.

Conclusion: As a countermeasure, the sliding seat with appropriate restraint forces can significantly reduce whiplash neck injury risk in rear impacts of low, medium, and high severities with no negative effects on other crash load cases.     

Evaluation of developmental metrics for utilization in a pediatric advanced automatic crash notification algorithm

Objective: Appropriate treatment at designated trauma centers (TCs) improves outcomes among injured children after motor vehicle crashes (MVCs). Advanced Automatic Crash Notification (AACN) has shown promise in improving triage to appropriate TCs. Pediatric-specific AACN algorithms have not yet been created. To create such an algorithm, it will be necessary to include some metric of development (age, height, or weight) as a covariate in the injury risk algorithm. This study sought to determine which marker of development should serve as a covariate in such an algorithm and to quantify injury risk at different levels of this metric.

Methods: A retrospective review of occupants age < 19 years within the MVC data set NASS-CDS 2000–2011 was performed. R² values of logistic regression models using age, height, or weight to predict 18 key injury types were compared to determine which metric should be used as a covariate in a pediatric AACN algorithm. Clinical judgment, literature review, and chi-square analysis were used to create groupings of the chosen metric that would discriminate injury patterns. Adjusted odds of particular injury types at the different levels of this metric were calculated from logistic regression while controlling for gender, vehicle velocity change (delta V), belted status (optimal, suboptimal, or unrestrained), and crash mode (rollover, rear, frontal, near-side, or far-side).

Results: NASS-CDS analysis produced 11,541 occupants age < 19 years with nonmissing data. Age, height, and weight were correlated with one another and with injury patterns. Age demonstrated the best predictive power in injury patterns and was categorized into bins of 0–4 years, 5–9 years, 10–14 years, and 15–18 years. Age was a significant predictor of all 18 injury types evaluated even when controlling for all other confounders and when controlling for age- and gender-specific body mass index (BMI) classifications. Adjusted odds of key injury types with respect to these age categorizations revealed that younger children were at increased odds of sustaining Abbreviated Injury Scale (AIS) 2+ and 3+ head injuries and AIS 3+ spinal injuries, whereas older children were at increased odds of sustaining thoracic fractures, AIS 3+ abdominal injuries, and AIS 2+ upper and lower extremity injuries.

Conclusions: The injury patterns observed across developmental metrics in this study mirror those previously described among children with blunt trauma. This study identifies age as the metric best suited for use in a pediatric AACN algorithm and utilizes 12 years of data to provide quantifiable risks of particular injuries at different levels of this metric. This risk quantification will have important predictive purposes in a pediatric-specific AACN algorithm.     

Transport company safety climate—The impact on truck driver behavior and crash involvement

Objective: The present study investigated the relationships between safety climate and driving behavior and crash involvement.

Methods: A total of 339 company-employed truck drivers completed a questionnaire that measured their perceptions of safety climate, crash record, speed choice, and aberrant driving behaviors (errors, lapses, and violations).

Results: Although there was no direct relationship between the drivers' perceptions of safety climate and crash involvement, safety climate was a significant predictor of engagement in risky driving behaviors, which were in turn predictive of crash involvement.

Conclusions: This research shows that safety climate may offer an important starting point for interventions aimed at reducing risky driving behavior and thus fewer vehicle collisions.     

Exploratory multinomial logit model–based driver injury severity analyses for teenage and adult drivers in intersection-related crashes

Objective: Teenage drivers are more likely to be involved in severely incapacitating and fatal crashes compared to adult drivers. Moreover, because two thirds of urban vehicle miles traveled are on signal-controlled roadways, significant research efforts are needed to investigate intersection-related teenage driver injury severities and their contributing factors in terms of driver behavior, vehicle–infrastructure interactions, environmental characteristics, roadway geometric features, and traffic compositions. Therefore, this study aims to explore the characteristic differences between teenage and adult drivers in intersection-related crashes, identify the significant contributing attributes, and analyze their impacts on driver injury severities.

Methods: Using crash data collected in New Mexico from 2010 to 2011, 2 multinomial logit regression models were developed to analyze injury severities for teenage and adult drivers, respectively. Elasticity analyses and transferability tests were conducted to better understand the quantitative impacts of these factors and the teenage driver injury severity model's generality.

Results: The results showed that although many of the same contributing factors were found to be significant in the both teenage and adult driver models, certain different attributes must be distinguished to specifically develop effective safety solutions for the 2 driver groups.

Conclusions: The research findings are helpful to better understand teenage crash uniqueness and develop cost-effective solutions to reduce intersection-related teenage injury severities and facilitate driver injury mitigation research.     

Examining motorcyclists' postcrash impressions: A qualitative study

Objective: Motorcycle-related crashes and injuries continue to be of great concern in Iran. This study seeks to explore how motorcyclists' perspectives and impressions of a crash are shaped and influence their future riding behaviors.

Methods: This was a qualitative study conducted in 3 major cities in Iran between March 2011 and February 2012. Participants included 31 male motorcyclists, of whom 22 participated in 4 focus groups and 9 in in-depth interviews. Findings were derived through the thematic method of analysis.

Results: Six delineated themes suggest different factors that influence riders' postcrash impressions. These include (1) opposing reactions from family and peers postcrash; (2) the motorcyclist's perception of his or her ability to handle risky road situations; (3) risk-taking attributes; (4) perceived responsibility in meeting family needs; (5) the severity of the crash-related injury; and (6) elapsed time from the crash experience.

Conclusions: Riders' postcrash impressions were formed by the opposing reactions of their family and peers to the crash experience (i.e., the index crash); the personality of riders, including being overconfident and a risk taker; familial obligations; feeling traumatized by the crash; and passage of time. These formed their perceptions, feelings, attitudes, and thoughts about the index crash.

These findings are an important step in understanding how perception and attitudes of motorcyclists are shaped and how these influence their future riding behavior. The needs for interventional studies to assess the effectiveness of road safety risk reduction programs aligned with the riders' degree of postcrash impressions are discussed.     

Powered two-wheeler riders' risk of crashes associated with filtering on urban roads

Objective: The objective of this study is to estimate the crash risk per kilometer traveled by powered two-wheeler (PTW) riders filtering through traffic on urban roads.

Methods: Using the traffic injury crashes recorded by the police over a period of 3 years on 14 sections of urban roads in the city of Marseille, France, and a campaign of observations of PTWs, the crash risk per kilometer traveled by PTWs filtering was estimated and compared to the risk of PTWs that did not filter.

Results: The results show that the risk of PTW riders being involved in injury crashes while filtering is significantly higher than the risk for riders who do not filter. For the 14 sections studied, it is 3.94 times greater (95% confidence interval [CI], 2.63, 5.89). This excess risk occurred for all PTW categories. Furthermore, no space appears to be safer than the others for filtering. Riders filtering forward along the axis of the carriageway, along bus lanes, or between traffic lanes (lane-splitting) all have a crash risk greater than the risk of those who do not filter.

Conclusions: All measures limiting the practice of filtering by PTWs on urban roads would probably contribute to improving the safety of their users.     

Analyzing pedestrian crash injury severity under different weather conditions

Objective: Pedestrians are the most vulnerable road users due to the lack of mass, speed, and protection compared to other types of road users. Adverse weather conditions may reduce road friction and visibility and thus increase crash risk. There is limited evidence and considerable discrepancy with regard to impacts of weather conditions on injury severity in the literature. This article investigated factors affecting pedestrian injury severity level under different weather conditions based on a publicly available accident database in Great Britain.

Method: Accident data from Great Britain that are publicly available through the STATS19 database were analyzed. Factors associated with pedestrian, driver, and environment were investigated using a novel approach that combines a classification and regression tree with random forest approach.

Results: Significant severity predictors under fine weather conditions from the models included speed limits, pedestrian age, light conditions, and vehicle maneuver. Under adverse weather conditions, the significant predictors were pedestrian age, vehicle maneuver, and speed limit.

Conclusions: Elderly pedestrians are associated with higher pedestrian injury severities. Higher speed limits increase pedestrian injury severity. Based on the research findings, recommendations are provided to improve pedestrian safety.     

Motorcycle fuel tanks and pelvic fractures: A motorcycle fuel tank syndrome

Objective: Pelvic injuries are a serious and commonly occurring injury to motorcycle riders involved in crashes, yet there has been limited research investigating the mechanisms involved in these injuries. This study aimed to investigate the mechanisms involved in pelvic injuries to crashed motorcyclists.

Method: This study involved in-depth crash investigation and 2 convenience-based data sets were used. These data sets investigated motorcycle crashes in the Sydney, Newcastle, and Adelaide regions. Participants included motorcycle riders who had crashed either on a public road or private property within the study areas. The mechanism of injury and the type of injuries were investigated.

Results: The most frequent cause of pelvic injuries in crashed motorcyclists was due to contact with the motorcycle fuel tank during the crash (85%). For riders who had come into contact with the fuel tank, the injury types were able to be grouped into 3 categories based on the complexity of the injury. The complexity of the injury appeared to increase with impact speed but this was a nonsignificant trend. The pelvic injuries that did not occur from contact with the fuel tank in this sample differed in asymmetry of loading and did not commonly involve injury to the bladder. They were commonly one-sided injuries but this differed based on the point of loading; however, a larger sample of these injuries needs to be investigated.

Conclusion: Overall improvements in road safety have not been replicated in the amelioration of pelvic injuries in motorcyclists and improvements in the design of crashworthy motorcycle fuel tanks appear to be required.     

Ankle fracture patterns in drivers are associated with femoral fracture,higher BMI,and advanced age

Objective: Despite advances in vehicle safety systems, motor vehicle crashes continue to cause ankle fractures. This study attempts to provide insight into the mechanisms of injury and to identify the at-risk population groups.

Methods: A study was made of ankle fractures patients treated at an urban level 1 trauma center following motor vehicle crashes, with a concurrent analysis of a nationally representative crash data set. The national data set focused on ankle fractures in drivers involved in frontal crashes. Statistical analysis was applied to the national data set to identify factors associated with fracture risk.

Results: Malleolar fractures occurred most frequently in the driver's right foot due to pedal interaction. The majority of complex/open fractures occurred in the left foot due to interaction with the vehicle floor. These fractures occurred in association with a femoral fracture, but their broad injury pattern suggests a range of fracture causation mechanisms. The statistical analysis indicated that the risk of fracture increased with increasing driver body mass index (BMI) and age.

Conclusions: Efforts to reduce the risk of driver ankle injury should focus on right foot and pedal interaction. The range of injury patterns identified here suggest that efforts to minimize driver ankle fracture risk will likely need to consider injury tolerances for flexion, pronation/supination, and axial loading in order to capture the full range of injury mechanisms. In the clinical environment, physicians examining drivers after a frontal crash should consider those who are older or obese or who have severe femoral injury without concurrent head injury as highly suspicious for an ankle injury.     

Effects of rearview cameras and rear parking sensors on police-reported backing crashes

Objective: The objective of this study was to examine the effectiveness of rearview cameras, rear parking sensors, and both systems combined in preventing police-reported backing crashes.

Methods: Negative binomial regression was used to compare rates of police-reported backing crash involvements per insured vehicle year in 22 U.S. states during 2009–2014 between passenger vehicle models with backing technologies and the same vehicle models where the optional systems were not purchased, controlling for other factors affecting crash risk. Rearview cameras were examined from four automakers, rear parking sensors from 2 automakers, and both systems combined from a single automaker.

Results: Rearview cameras reduced backing crash involvement rates by 17%. Reductions were larger for drivers 70 and older (36%) than for drivers younger than 70 (16%); however, estimates for older and younger drivers did not differ significantly from one another. The Buick Lucerne's rear parking sensor system reduced backing crash involvement rates significantly by 34%, but the reduction for Mercedes-Benz vehicles fit with a sensor system was small and not statistically significant. When averaged between the 2 automakers, effects were significantly larger for drivers 70 and older (38% reduction) than for drivers younger than 70 (1% increase); effects were significant for older but not younger drivers. Backing crash involvement rates were 13% lower among Mercedes-Benz vehicles with a rearview camera and parking sensors than among vehicles without, but this finding was not significant.

Discussion: Rearview cameras are effective in preventing police-reported backing crashes. Effects of rear parking sensors are less straightforward; it is unclear whether the Buick Lucerne system's benefits are due to the older age of its drivers, characteristics of the vehicle or system, or a combination. Systems may be especially beneficial to older drivers who might have limitations that make backing challenging. Although effect estimates did not differ significantly between older and younger drivers for both system types, the magnitude of the differences was large and the pattern of results was consistent across 6 of the 7 systems examined. When rear visibility systems become required equipment on new passenger vehicles in 2018, rearview cameras can be expected to prevent 1 in 6 backing crashes reported to police that involve equipped vehicles.     

Serious road injuries in The Netherlands dissected

Objective: This article discusses the characteristics and injury patterns of serious road injuries (Maximum Abbreviated Injury Scale [MAIS] 2+ inpatients) in The Netherlands.

Methods: In The Netherlands, the actual number of serious injuries is estimated by linking police data to hospital data. The distribution of serious road injuries over (1) travel mode and gender and (2) crash type and age are compared for the years 2000 and 2011. Moreover, the distribution of the injuries over the body regions is illustrated using colored injury body profiles.

Results: The number of serious injuries is higher for men than for women and increased from 16,500 in 2000 to 19,700 in 2011. In 2011, about half (51%) of the serious road injuries were due to a bicycle crash not involving a motor vehicle. The share of casualties aged 60 years and older is relatively high (43% in 2011) in these crashes. The injury body profiles show that head injuries (31%) and injuries to the lower extremities (37%) are most prevalent. Compared to other travel modes, pedestrians and riders of powered 2-wheelers relatively often sustain lower-leg injuries compared to other travel modes. Head injuries are most prevalent in cyclists who are injured in a crash with a motorized vehicle. Cyclists who are injured in a crash not involving a motor vehicle and casualties of 60 years and older relatively often include hip or upper-leg injuries.

Conclusion: The characteristics of serious road injuries differ from those of fatalities and the distribution of injuries over the body differs by travel mode, gender, and age.     

Driver injury severity related to inclement weather at highway–rail grade crossings in the United States

Objective: Previous studies on crash modeling at highway–rail grade crossings were aimed at exploring the factors that are likely to increase the crash frequencies at highway–rail grade crossings. In recent years, modeling driver's injury severity at highway–rail grade crossings has received interest. Because there were substantial differences among different weather conditions for driver's injury severity, this study attempts to explore the impact of weather influence on driver injury at highway–rail grade crossing.

Method: Utilizing the most recent 10 years (2002–2011) of highway–rail grade crossing accident data, this study applied a mixed logit model to explore the determinants of driver injury severity under different weather conditions at highway–rail grade crossing.

Results: Analysis results indicate that drivers' injury severity at highway–rail grade crossings is strongly different for different weather conditions. It was found that the factors significantly impacting driver injury severity at highway–rail grade crossings include motor vehicle speed, train speed, driver's age, gender, area type, lighting condition, highway pavement, traffic volume, and time of day.

Conclusions: The findings of this study indicate that crashes are more prevalent if vehicle drivers are driving at high speed or the oncoming trains are high speed. Hence, a reduction in speed limit during inclement weather conditions could be particularly effective in moderating injury severity, allowing more reaction time for last-minute maneuvering and braking in moments before impacts. In addition, inclement weather-related crashes were more likely to occur in open areas and highway–rail grade crossings without pavement and lighting. Paved highway–rail grade crossings with installation of lights could be particularly effective in moderating injury severity.     

An empirical bayes safety evaluation of tram/streetcar signal and lane priority measures in Melbourne

Objective: Streetcars/tram systems are growing worldwide, and many are given priority to increase speed and reliability performance in mixed traffic conditions. Research related to the road safety impact of tram priority is limited. This study explores the road safety impacts of tram priority measures including lane and intersection/signal priority measures.

Method: A before–after crash study was conducted using the empirical Bayes (EB) method to provide more accurate crash impact estimates by accounting for wider crash trends and regression to the mean effects. Before–after crash data for 29 intersections with tram signal priority and 23 arterials with tram lane priority in Melbourne, Australia, were analyzed to evaluate the road safety impact of tram priority.

Results: The EB before–after analysis results indicated a statistically significant adjusted crash reduction rate of 16.4% after implementation of tram priority measures. Signal priority measures were found to reduce crashes by 13.9% and lane priority by 19.4%. A disaggregate level simple before–after analysis indicated reductions in total and serious crashes as well as vehicle-, pedestrian-, and motorcycle-involved crashes. In addition, reductions in on-path crashes, pedestrian-involved crashes, and collisions among vehicles moving in the same and opposite directions and all other specific crash types were found after tram priority implementation.

Conclusions: Results suggest that streetcar/tram priority measures result in safety benefits for all road users, including vehicles, pedestrians, and cyclists. Policy implications and areas for future research are discussed.     

Health burden of serious road injuries in the Netherlands

Background: The consequences of injuries in terms of disabilities and health burden are relevant for policy making. This article provides an overview of the current knowledge on this topic and discusses the health burden of serious road injuries in The Netherlands.

Methods: The overview of current knowledge on disabilities following a road crash is based on a literature review. The health burden of serious road injuries is quantified in terms of years lived with disability (YLD), by combining incidence data from the Dutch hospital discharge register with information about temporary and lifelong disability.

Results: Literature shows that road traffic injuries can have a major impact on victims' physical and psychological well-being and functioning. Reported proportions of people with disability vary between 11 and 80% depending on the type of casualties, time elapsed since the crash, and the health impacts considered. Together, all casualties involving serious injuries in The Netherlands in 2009 account for about 38,000 YLD, compared to 25,000 years of life lost (YLL) of fatalities. Ninety percent of the burden of injury is due to lifelong consequences that are experienced by 20% of all those seriously injured in road accidents. Lower leg injuries and head injuries represent a high share in the total burden of injury as have cyclists that are injured in a crash without a motorized vehicle. Pedestrians and powered 2-wheeler users show the highest burden of injury per casualty.

Conclusion: Given their major impacts and contribution to health burden, road policy making should also be aimed at reducing the number of serious road injuries and limiting the resulting health impacts.     

A new method to assess the deformations of internal organs of the abdomen during impact

Objectives: Due to limitations of classic imaging approaches, the internal response of abdominal organs is difficult to observe during an impact. Within the context of impact biomechanics for the protection of the occupant of transports, this could be an issue for human model validation and injury prediction.

Methods: In the current study, a previously developed technique (ultrafast ultrasound imaging) was used as the basis to develop a protocol to observe the internal response of abdominal organs in situ at high imaging rates. The protocol was applied to 3 postmortem human surrogates to observe the liver and the colon during impacts delivered to the abdomen.

Results: The results show the sensitivity of the liver motion to the impact location. Compression of the colon was also quantified and compared to the abdominal compression.

Conclusions: These results illustrate the feasibility of the approach. Further tests and comparisons with simulations are under preparation.     

Risk of serious injury of occupants involved in frontal crashes of cab-over-type trucks

Objectives: Truck vehicles (TVs) have a different structure and stiffness than non-TVs and are used commercially for transporting goods. This study aimed to analyze whether truck occupants have a greater risk of serious injury than those of other types of vehicles.

Methods: Crash data were obtained from the Korean In-Depth Data Analysis Study (KIDAS) for calendar years 2011–2016. Vehicles involved in frontal crash were included and classified into TVs and non-TVs (passenger cars and sports utility vehicles). We compared the demographic characteristics and serious injuries by body region between the 2 groups and analyzed factors that contributed to the serious injury severity from frontal crashes.

Results: The analysis was based on 884 occupants; 177 (20.0%) were in TVs and 707 (80.0%) were in non-TVs. Non-TVs had more frontal airbags deployments than TVs (50.9% vs. 3.4%, P <.01). TV occupants were 4.8 times more likely to have a serious lower extremity (LE) injury (adjusted odds ratio [AOR] = 4.820; 95% confidence interval [CI], 2.407–9.653) and 2.5 times to have a serious abdominal injury (AOR = 2.465; 95% CI, 1.108–5.487) compared to non-TV occupants.

Conclusions: Truck occupants had more serious LE and abdominal injuries than those of other types of vehicles in frontal crashes. Structural improvement and legislative efforts to develop safety systems are necessary to improve the safety of truck occupants.     

Repeatability study of replicate crash tests: A signal analysis approach

Objective: To provide an objective basis on which to evaluate the repeatability of vehicle crash test methods, a recently developed signal analysis method was used to evaluate correlation of sensor time history data between replicate vehicle crash tests. The goal of this study was to evaluate the repeatability of rollover crash tests performed with the Dynamic Rollover Test System (DRoTS) relative to other vehicle crash test methods.

Methods: Test data from DRoTS tests, deceleration rollover sled (DRS) tests, frontal crash tests, frontal offset crash tests, small overlap crash tests, small overlap impact (SOI) crash tests, and oblique crash tests were obtained from the literature and publicly available databases (the NHTSA vehicle database and the Insurance Institute for Highway Safety TechData) to examine crash test repeatability.

Results: Signal analysis of the DRoTS tests showed that force and deformation time histories had good to excellent repeatability, whereas vehicle kinematics showed only fair repeatability due to the vehicle mounting method for one pair of tests and slightly dissimilar mass properties (2.2%) in a second pair of tests. Relative to the DRS, the DRoTS tests showed very similar or higher levels of repeatability in nearly all vehicle kinematic data signals with the exception of global X′ (road direction of travel) velocity and displacement due to the functionality of the DRoTS fixture. Based on the average overall scoring metric of the dominant acceleration, DRoTS was found to be as repeatable as all other crash tests analyzed. Vertical force measures showed good repeatability and were on par with frontal crash barrier forces. Dynamic deformation measures showed good to excellent repeatability as opposed to poor repeatability seen in SOI and oblique deformation measures.

Conclusions: Using the signal analysis method as outlined in this article, the DRoTS was shown to have the same or better repeatability of crash test methods used in government regulatory and consumer evaluation test protocols.