Patterns and mechanisms of pedestrian injuries induced by vehicles with flat-front shape

The association between passenger-vehicle front-end profiles and pedestrian injury severity in motor vehicle crashes

INTRODUCTION

Vehicles play an important role in pedestrian injury risk in crashes. This study examined the association between vehicle front-end geometry and the risk of fatal pedestrian injuries in motor vehicle crashes.

METHOD

A total of 17,897 police-reported crashes involving a single passenger vehicle and a single pedestrian in seven states were used in the analysis. Front-end profile parameters of vehicles (2,958 vehicle makes, series, and model years) involved in these crashes were measured from vehicle profile photos, including hood leading edge height, bumper lead angle, hood length, hood angle, and windshield angle. We defined a front-end-shape indicator based on the hood leading edge height and bumper lead angle. Logistic regression analysis evaluated the effects of these parameters on the risk that a pedestrian was fatally injured in a single-vehicle crash.

RESULTS

Vehicles with tall and blunt, tall and sloped, and medium-height and blunt front ends were associated with significant increases of 43.6%, 45.4%, and 25.6% in pedestrian fatality risk, respectively, when compared with low and sloped front ends. There was a significant 25.1% increase in the risk if a hood was relatively flat as defined in this study. A relatively long hood and a relatively large windshield angle were associated with 5.9% and 10.7% increases in the risk, respectively, but the increases were not significant.

CONCLUSIONS

Vehicle front-end profiles that were significantly associated with increased pedestrian fatal injury risk were identified.

PRACTICAL APPLICATIONS

Automakers can make vehicles more pedestrian friendly by designing vehicle front ends that are lower and more sloped. The National Highway Traffic Safety Administration (NHTSA) can consider evaluations that account for the growing hood heights and blunt front ends of the vehicle fleet in the New Car Assessment Program or regulation.

Vehicle front-end geometry and in-depth pedestrian injury outcomes

OBJECTIVE

Large passenger vehicles have consistently demonstrated an outsized injury risk to pedestrians they strike, particularly those with tall, blunt front ends. However, the specific injuries suffered by pedestrians in these crashes as well as the mechanics of those injuries remain unclear. The current study was conducted to explore how a variety of vehicle measurements affect pedestrian injury outcomes using crash reconstruction and detailed injury attribution.

METHODS

We analyzed 121 pedestrian crashes together with a set of vehicle measurements for each crash: hood leading edge height, bumper lead angle, hood length, hood angle, and windshield angle.

RESULTS

Consistent with past research, having a higher hood leading edge height increased pedestrian injury severity, especially among vehicles with blunt front ends. The poor crash outcomes associated with these vehicles stem from greater injury risk and severity to the torso and hip from these vehicles' front ends and a tendency for them to throw pedestrians forward after impact.

CONCLUSIONS

The combination of vehicle height and a steep bumper lead angle may explain the elevated pedestrian crash severity typically observed among large vehicles.

A Study on Influence of Minivan Front-End Design and Impact Velocity on Pedestrian Thorax Kinematics and Injury Risk

Thoracic injuries occur frequently in minivan-to-pedestrian impact accidents and can cause substantial fatalities. The present research work investigates the human thoracic responses and injury risks in minivan-to-pedestrian impacts, when changing the minivan front-end design and the impact velocity, by using computational biomechanics model. We employed three typical types of minivan model of different front-end designs that are quite popular in Chinese market and considered four impact velocities (20, 30, 40, and 50 km/h). The contact time of car to thorax region (CTCTR), thorax impact velocity, chest deformation, and thoracic injury risks were extracted for the investigation. The results indicate that the predicted pedestrian kinematics, injury responses, and thoracic injury risks are strongly affected by the variation of the minivan front-end design and impact velocity. The pedestrian thoracic injury risks increase with the increasing vehicle impact velocity. It is also revealed that the application of the extra front bumper is beneficial for reducing the thoracic injury risk, and a relatively flatter minivan front-end design gives rise to a higher thoracic injury risk. This study is expected to be served as theoretical references for pedestrian protection design of minivans.

Grouping of body areas affected in traffic accidents. A cohort study

BACKGROUND

Traffic accidents are considered a public health problem and, according to the World Health Organization, currently is the eighth cause of death in the world. Specifically, pedestrians, cyclists and motorcyclists contribute half of the fatalities. Adequate clinical management in accordance with aggregation patterns of the body areas involved, as well as the characteristics of the accident, will help to reduce mortality and disability in this population.

METHODS

Secondary data analysis of a cohort of patients involved in traffic accidents and admitted to the emergency room (ER) of a high complexity hospital in Medellín, Colombia. They were over 15 years of age, had two or more injuries in different areas of the body and had a hospital stay of more than 24 h after admission. A cluster analysis was performed, using Ward's method and the linfinity similarity measure, to obtain clusters of body areas most commonly affected depending on the type of vehicle and the type of victim.

RESULTS

Among 2445 patients with traffic accidents, 34% (n = 836) were admitted into the Intensive Care Unit (ICU) and the overall hospital mortality rate was 8% (n = 201). More than 50% of the patients were motorcycle riders but mortality was higher in pedestrian-car accidents (16%, n = 34). The clusters show efficient performance to separate the population depending on the severity of their injuries. Pedestrians had the highest mortality after having accidents with cars and they also had the highest number of body parts clustered, mainly on head and abdomen areas.

CONCLUSIONS

Exploring the cluster patterns of injuries and body areas affected in traffic accidents allow to establish anatomical groups defined by the type of accident and the type of vehicle. This classification system will accelerate and prioritize ER-care for these population groups, helping to provide better health care services and to rationalize available resources.

Traffic accident or dumping? - Striking results of a traffic accident reconstruction

An atypical traffic accident scenario should be investigated directly at the crash site from all concerned professions, especially police men, forensic pathologists and technical experts, to get a personal overview and impression of the situation and the opportunity for interdisciplinary discussion. We present the rare case of a fatal traffic accident on a German motorway which was initially thought to be an accidental discovery of dumping a corpse. Based on autopsy findings, the technical investigation and the accident reconstruction, this case was solved as a spectacular form of a collision between a pedestrian and a bonnet-front car, which was not described elsewhere in scientific literature to the best of our knowledge. The pedestrian was hit in an upright body position, was lifted up by the car, smashed the windscreen and flew over the car with several body rotations. His flight curve ends directly at the roof of the car during brake processing, where the body touched the roof, smashed the rear-window and landed in the trunk. Based on the technical investigation, the driver of the car was not able to hide the accident. However, the pedestrian could have avoided the collision if he did not cross the motorway on foot.

Pedestrian injury patterns and risk in minibus collisions in China

Background

The minibus, with a nearly flat front, is widely used in China, especially in the underdeveloped regions, and results in large numbers of pedestrian injuries and deaths. The purpose of this study was to determine the injury patterns and risk for pedestrians involved in these crashes.

Material/Methods

We conducted an in-depth investigation of minibus/pedestrian accidents in Chongqing, China, occurring between September 2000 and April 2014. The enrolled pedestrians was classified into 3 groups: young (aged 14–44 years), middle-aged (aged 45–59 years), and elderly (aged over 60 years). Pedestrian injuries were coded according to the Abbreviated Injury Scale (AIS).

Results

A total of 109 pedestrians, with an average age of 55.7±16.2 years, were injured or killed – 30.3% were young, 23.9% were middle-aged, and 45.9% were elderly. Pedestrians hit by a minibus had a high proportion of head, chest, and extremity injuries – 84.4%, 50.5%, and 52.3%, respectively. In addition, impact speeds in excess of 75 km/h all ultimately resulted in fatalities. At an impact speed of 30 km/h, the risk of pedestrian fatality and AIS3+ injury are approximately 12.0% and 37.2%, respectively. At 50 km/h the risks are 65.2% and 96.9%, respectively, and at 70 km/h the risks are 96.3% and 99.9%, respectively.

Conclusions

A higher likelihood of chest injury was associated with being older and impact speed of over 40 km/h in minibus/pedestrian collision. Our data suggest that the injury patterns of pedestrians in minibus collisions differ from that in other vehicle/pedestrian collisions. These findings could contribute to better understanding of the injury patterns and risk of pedestrian in minibus collisions in China, which may play an important role in developing measures to improve traffic safety.

The modern holy shroud

Testimonies disclosed that a 44-year-old pedestrian was struck head-on by a truck while she was roaming on the motorway; at the time of collision, the truck was travelling at a speed of about 90 km/h. In the second phase of the collision, the pedestrian was projected about 100 m before her body was run over by the truck and then by a car. The autopsy revealed extensive mutilations, making it impossible to verify the testimonies of witnesses to the collision as regards the pedestrian's position at the moment of the first impact. However, the reports produced by the technical expert and the forensic pathologist were able to confirm the testimonies, based on an impact zone on the front panel of the cab of the truck, where part of the pedestrian's face was reproduced like a "modern holy shroud".