Have pedestrian subsystem tests improved passenger car front shape?

Abstract

Subsystem impactor tests are the main approaches for evaluation of safety performance of vehicle front design for pedestrian protection in legislative regulations. However, the main aspects of vehicle safety for pedestrians are shape and stiffness, and though it is clear that subsystem impact tests encourage lower vehicle front stiffness, it is unclear whether they promote improved vehicle front shapes for pedestrian protection. The purpose of this paper is therefore to investigate the effects of European pedestrian safety regulations on passenger car front shape and pedestrian injury risk using recent German In-Depth Accident Study (GIDAS) pedestrian collision data and numerical simulations. Firstly, a sample of 579 pedestrian collision cases involving 190 different car models between 2000-2015 extracted from the GIDAS was used to compare front-end shapes of passenger cars manufactured before and after the legislative pedestrian safety regulations were introduced in Europe. The focus was on changes in passenger car front shape and differences in pedestrian AIS2+ (Abbreviated Injury Scale at least level 2) leg, pelvis/femur and head injury risk observed in collisions. Multi-body simulations were also used to assess changes in vehicle aggressivity due to the observed changes in vehicle shape. The results show that newer passenger cars tend to have a flatter and wider bumper, higher bonnet leading edge, shorter and steeper bonnet and a shallower windscreen. Both the collision data and the numerical simulations indicate that newer passenger car front bumper designs are significantly safer for pedestrians' legs. However, the results also show that the higher bonnet leading edge in newer passenger cars is poor for pedestrian pelvis/femur protection, even though newer cars show an obviously lower AIS2+ injury risk to younger pedestrians in collisions. Newer cars have a lower AIS2+ head injury risk for pedestrians in collisions, but the numerical analysis indicate that this is not likely due to shape changes in passenger car fronts. Overall, the introduction of pedestrian safety regulations has resulted in reductions in pedestrian injury risk, but further benefits would accrue from tests which promote a lower bonnet leading edge. The influence of vehicle shape on pedestrian head injury risk remains unclear.

Method to Assess and Enhance Vulnerable Road User Safety during Impact Loading

“…Nowadays, numerical systems can improve biomechanical criteria as well as head-protective systems, facilitating forensic sciences and the reconstruction of accidents, diagnosis and prediction of injuries and enables researchers to gain knowledge in the field of head injuries. The use of numerical systems has contributed to reduction of VRU injuries-these aspects were presented by eminent researchers in References [62,[67][68][69][70]. Therefore, the author put forward a coherent methodology, based on numerical and experimental achievements and proposed some technical countermeasures to improve road safety for VRUs.…”

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

“…The limitations of this paper mainly rely on two aspects. The primary limitation is that the current study focuses on the evaluation of pedestrian thoracic injury risks, but in actual fact, pedestrian head and lower extremity pose more significant fatal and severe injuries, which has been identified in vast of related researches [ 3 , 4 , 15 , 46 , 47 ], and they were not considered in our study. Thus, from the perspective of pedestrian injury prevention involved in vehicle collisions, major research concerns need to be concentrated on the head and lower extremity injuries despite the importance/significance of thoracic injury inflicted when struck by minivan found both in the literature and in the current study.…”

“…Another limitation of this study is that the potential influence of the modifications of the minivan front-end shape, found to be conductive to reduce pedestrian thoracic injury risk in the current study, on the pedestrian lower extremity injury is not investigated. Since such influence has been analyzed in sedan-to-pedestrian impact accident scenarios [ 46 , 48 ], further work may need to be conducted to identify it in the future research.…”

A Computational Biomechanics Human Body Model Coupling Finite Element and Multibody Segments for Assessment of Head/Brain Injuries in Car-To-Pedestrian Collisions

“…Head injury has been identified to be the most common cause of pedestrian fatality in pedestrian accidents, and substantial research efforts have been made focusing on pedestrian head injury biomechanics and prevention [25][26][27][28][29]. In this field, the FE model was frequently used for assessment of the pedestrian brain tissue injury, as the importance of brain deformation on traumatic brain injury had been extensively confirmed.…”

“…Compared to the MB model, the advantage of the FE model, being able to represent detailed human anatomical structure, makes it possible to study human tissue level injuries. However, the FE model requires high computational resources for the model adjustment and computations, which means that it is not realistic to conduct complicated traffic accident reconstruction using solely the FE model [25].Head injury has been identified to be the most common cause of pedestrian fatality in pedestrian accidents, and substantial research efforts have been made focusing on pedestrian head injury biomechanics and prevention [25][26][27][28][29]. In this field, the FE model was frequently used for assessment of the pedestrian brain tissue injury, as the importance of brain deformation on traumatic brain injury had been extensively confirmed.…”