In-depth real-world bicycle accident reconstructions

Abstract

Use of bicycles on a large scale, encouraged in the context to develop an eco-friendly environment, is facing today a range of barriers. One of these barriers identified by researchers and governments is observed to include ‘road safety’. Hence, it is necessary to set up a protection system for bicyclists especially for the cephalic segment. Currently only few studies are available concerning the head impact loading in case of real accidents. Therefore, the objective of this work is to improve the knowledge of bicyclist head trauma by following a methodology to reconstruct real-world accidents. A step is to identify the initial condition of head impact in case of real accidents. Head impact velocity and head impact area are extracted and implemented in the last generation of head injury prediction tool to simulate the head trauma by impacting directly the Strasbourg University Finite Element Head Model (SUFEHM) on the vehicle structures. The present study can be divided into three activities, i.e. obtain real bicyclist accidents’ data issued from in-depth accident investigation databases, reconstruct cyclist body kinematics to obtain the initial conditions of the head just before the impact, and simulate head impact to evaluate the head loading during impact and the injury risk. A total of 24 bicyclists’ accident cases with head injuries have been selected from both French and German accident databases. For each accident case, body kinematics has been simulated using Madymo® software. Two human multi-body models were used: 8 accident cases have been reconstructed by IFSTTAR using its owned developed human model and 18 accident cases have been reconstructed by Unistra using the human pedestrian TNO model. The results show that head is impacted more often on top parietal zone, and the mean impact velocity is 6.8 ± 2.7 m/s with 5.5 ± 3.0 m/s and 3.4 ± 2.1 m/s for normal and tangential components, respectively. Among these real accidents, 19 cases were selected for finite element computations by coupling the human head model and a windscreen model whose properties were extracted from literature. All reconstructed head impact gave results in accordance with the damage actually incurred to the victims

Head impact in a snowboarding accident

“…To further develop understanding of the mechanisms involved in snowboarding head injuries, we believe that the next step is to apply head impact conditions obtained with our model as initial conditions of a detailed finite element model, as described in Bourdet et al. ().…”

“…In impact biomechanics and transport safety, multi‐body human modeling and numerical simulations are widely used to complement experimental investigations to analyze the effects of accident conditions on human body kinematics and injury mechanisms (Serre et al., ; Bourdet et al., ). These numerical methods have been successfully used for vulnerable road users (pedestrians, cyclists, and motorcyclists), but never to our knowledge to investigate snow sport accidents.…”

Child Safety on Various Bicycle-Mounted Seats During Vehicle Impact

“…In terms of the impacting direction of the full-scale test, most of impact scenarios in literature are described in this way (Lindman et al 2015). To exclude influences of the kinematics out of initial leg position or general cyclist posture in the moment of first contact between bicycle and vehicle, the dummies posture is equal in all simulation cases (Bourdet et al 2014).…”

Development of the STAR Evaluation System for Assessing Bicycle Helmet Protective Performance

“…A cyclist's head nearly always approaches a surface at an angle during a crash, termed an oblique impact. 5,41 Standards specify drop tests in a direction normal to the impact surface. Oblique impact testing using a biofidelic headform capable of measuring both linear and rotational kinematics would enhance assessment of helmet performance in reducing concussion risk.…”