Browse Topic: Pedestrian injuries

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Computational and Experimental Analysis of Head Injury Criteria (HIC) in Frontal Collision of Car with Pedestrian2019-26-00161/9/2019
Road accident between pedestrian and motor vehicle causes severe injuries and even death of pedestrian. The accident statistics show that the possibility of injury to pedestrian is higher in case of collision with car on busy roads. In car and pedestrian collisions, the pedestrian’s head hits with car bonnet and suffer from multiple injuries such as skull fractures and brain injury. The role of car bonnet structural strength plays an important role in pedestrian head injury level. To provide enough structural strength the high bonnet thickness is provided with under bonnet stiffeners, however thick bonnet and stiffeners reduces deformation of the bonnet during collision and increases injury level to pedestrian. Hence optimum bonnet thickness, least number and geometry of stiffeners and enough structural strength is important for bonnet to reduce injury level. The aim of this study is to analyse the effect of car bonnet thickness, number and arrangement of under bonnet stiffeners on head injury levels with the help of head injury criteria (HIC). Head Injury Criteria (HIC) is a measure of the likelihood of head injury arising from an impact during a car crash. It indicatesthe level of injury caused during a particular crash. A typical modern car bonnet is selected for investigation with variety of bonnet material thickness and different configurations of under bonnet stiffeners and head injury criteria (HIC) is computed with the help of computer modelling. Further, head linear velocity, acceleration and head injury risk are predicted for probability of skull fracture. The geometry of bonnet is optimized with the help of optimization technique and optimized bonnet geometry is validated experimentally by designing a bonnet test facility and head form imparter.
Thombare, Dr. Dhananjay G
Ground Landing Mechanisms in Vehicle-To-Pedestrian Impacts Based on Accident Video Records2018-01-10444/3/2018
Accident data have shown that the pedestrian injuries resulting from contact with the ground are serious and may even be worse than the injuries resulting from the primary contact with the vehicle. The landing mechanisms, including the pedestrian trajectory and subsequent sequential body region contacts to the ground, are the basis for understanding the ground impact injuries of pedestrians. However, the landing mechanisms of pedestrian are too complicated to be categorized via investigation of the collision information after an accident has occurred. Nowadays, pedestrian kinematics after vehicle impacts can be observed from the accident videos that have been recorded by road monitoring and driver recorders. This study was aimed at investigating the pedestrian landing mechanisms and analyzing the influencing factors. In the current study, 134 pedestrian cases (involving 136 pedestrians) were selected from the internet, and 13 types of landing mechanisms were classified according to the fall kinematics and landing posture. Our results show that pedestrians who were thrown forward and hit the ground without a clear rotational tendency (ground landing mechanism II) accounted for the highest frequency, 49.3% in all cases. The landing mechanisms of pedestrians were affected by impact velocities and kinematic trajectories during vehicle impacts. The results of this study can benefit the development of vehicle safety systems that reduce pedestrian ground impact injuries.
Li, Quan, Han, Yong, Mizuno, Koji
Design of Front Structure of Vehicle for Pedestrian Headform Protection2017-01-12983/28/2017
Vehicle Hood being the face of a passenger car poses the challenge to meet the regulatory and aesthetic requirements. Urge to make a saleable product makes aesthetics a primary condition. This eventually makes the role of structure optimization much more important. Pedestrian protection- a recent development in the Indian automotive industry, known for dynamics of cost competitive cars, has posed the challenge to make passenger cars meeting the regulation at minimal cost. The paper demonstrates structure optimization of hood and design of peripheral parts for meeting pedestrian protection performance keeping the focus on low cost of ownership. The paper discusses development of an in-house methodology for meeting Headform compliance of a flagship model of Maruti Suzuki India Ltd., providing detailed analysis of the procedure followed from introduction stage of regulatory requirement in the project to final validation of the engineering intent. The paper presents the impact of major limitations, such as, usage of common platform, aesthetics of hood, height of hood and layout of safety devices present below the hood -on design of hood for meeting pedestrian compliance. The case becomes further difficult owing to limited time available. The paper unfolds the strategies used to reduce injury criteria: change in hood assembly structure (except outer panel), layout of surrounding parts design of frontal structure, design of new hood hinge and design of safety device (hood switch) for better strength. In addition to this, many proposals have been discussed in the paper to make a cost efficient yet qualitative passenger car.
Yadav, Kamlesh, Sinha, Abhishek, Khurana, Rajdeep Singh
Vulnerable Road User Safety Message Minimum Performance RequirementsJ2945/9_201703 (Current)3/21/2017
This document provides recommendations of safety message minimum performance requirements between a Vulnerable Road User (VRU) and a vehicle. It addresses the transmission of Personal Safety Messages (PSM) from road user devices carried by pedestrians, bicycle riders and public safety personnel, to provide driver and vehicle system awareness and potentially offer safety alerts to VRUs. This document includes the recommendation of standards profiles, function descriptions and minimum performance requirements for transmitting the SAE J2735-defined PSM [1] over a Dedicated Short Range Communications (DSRC) Wireless communication link as defined in the Institute of Electrical and Electronics Engineers (IEEE) 1609 and the IEEE 802.11 Standards [[1]]-[5]]. While other wireless media may be used to deliver the PSM, DSRC is explicitly assumed in this document, because of anticipated regulatory ruling in the United States and other countries requiring vehicles to be equipped with a DSRC-based safety system using V2V communication. This recommended practice is limited at this time to communications between the VRU device carried by walking pedestrians and DSRC equipped vehicles. Later versions may incorporate improvements based on field experience with this recommended practice and may include other provisions for communicating with other DSRC equipped devices, and with other VRUs.
V2X Vehicular Applications Technical Committee
Association of Impact Velocity with Risks of Serious Injuries and Fatalities to Pedestrians in Commercial Truck-Pedestrian Accidents2016-22-000711/7/2016
This study aimed to clarify the relationship between truck-pedestrian crash impact velocity and the risks of serious injury and fatality to pedestrians. We used micro and macro truck-pedestrian accident data from the Japanese Institute for Traffic Accident Research and Data Analysis (ITARDA) database. We classified vehicle type into five categories: heavy-duty trucks (gross vehicle weight [GVW] ≥11 × 103 kg [11 tons (t)], medium-duty trucks (5 × 103 kg [5 t] ≤ GVW < 11 × 103 kg [11 t]), light-duty trucks (GVW <5 × 103 kg [5 t]), box vans, and sedans. The fatality risk was ≤5% for light-duty trucks, box vans, and sedans at impact velocities ≤ 30 km/h and for medium-duty trucks at impact velocities ≤20 km/h. The fatality risk was ≤10% for heavy-duty trucks at impact velocities ≤10 km/h. Thus, fatality risk appears strongly associated with vehicle class. The results also revealed that a 10 km/h reduction in impact velocities could mitigate the severity of pedestrian injuries at impact velocities ≥30 km/h for all five analyzed vehicle types. Therefore, serious injuries and fatalities to pedestrians could be decreased by the development and deployment of collision mitigation systems (CMSs) to all vehicles, including to commercial trucks, because CMSs can detect pedestrians in even severe conditions, such as when the drive’s view is obstructed, and can reduce the impact velocity. The present results indicate that CMS design specifications should differ between vehicle types because of the strong dependence of serious-injury and fatality risks on vehicle type.
Matsui, Yasuhiro, Oikawa, Shoko, Sorimachi, Kazuhiro, Imanishi, Akira, Fujimura, Takeshi
Pre-Collision System for Toyota Safety Sense2016-01-14584/5/2016
Toyota Safety Sense is a safety system package developed to help drivers avoid accident types with a high frequency of occurrence. This paper deals with pre-collision system which forms the core of Toyota Safety Sense, especially Toyota Safety Sense P which uses a combined sensor configuration consisting of a monocular camera paired with millimeter wave radar, in order to achieve both high recognition performance and reliability. The use of a wide-angle monocular camera, millimeter wave radar integrated in the front grill emblem, and a collision determination algorithm for pedestrian targets enabled the development of a pre-collision system comprising detection capability of crossing pedestrians. Toyota has developed warning and pre-collision brake assist for driver to assist in avoiding a collision effectively; In addition, Pre-collision brake has achieved high level of performance for the drivers who cannot avoid a collision. Conformance checking with field driving data from various locations worldwide has proved in high safety performance compliant with global preventive safety assessment principles.
Ono, Ryuta, Ike, Wataru, Fukaya, Yuki
Design Optimization of Hood System for Pedestrian Headform Protection2016-28-02502/1/2016
Hood is the closure provided in the frontal portion of the vehicle for covering the engine room. Any component disposed in the frontal portion of the vehicle becomes important because of aesthetic as well as regulatory requirements. Introduction of new regulations like pedestrian protection brings new challenges for the original equipment manufacturers and the governing authorities. Introduction of Pedestrian Protection regulation, a recent development in the automotive industry, has thrown several questions in front of original equipment manufacturers. This work explains the procedure to address such question and the learning associated with it. With an attempt to comply Pedestrian regulation, following were the major challenges: 1 Common Platform and Engine 2 High Hood Styling 3 Limited freedom to increase vehicle front overhang 4 Location of hood switch With above mentioned constraints, a team of design, evaluation and testing set forth its aim to make the Hood system pedestrian headform compliant while giving priority to styling and common platform. Also the location of safety device, hood switch, can’t be changed which becomes a major constraint in reducing the HIC values as the gap required for energy absorption was not available between hood and member hood lock. This paper presents all the facets and the outcomes of this important activity. Final design corroboration was done at Physical testing laboratory. The scope of this work lies in the application of the learning obtained during the activity for future deployment on various models.
Yadav, Kamlesh, Thakur, Ruhi
Risks of Serious Injuries and Fatalities of Cyclists Associated with Impact Velocities of Cars in Car-Cyclist Accidents in Japan2015-22-001511/9/2015
The main purpose of this study is to define the relationship between the car impact velocity and serious injury risk or fatality risk of cyclists. The authors investigated the risks of serious injuries and fatalities of cyclists using vehicle-cyclist accident data from the database of the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. The vehicle types considered are sedans, mini vans, box vans, light passenger cars and light cargo vans. The results revealed that a 10-km/h decrease in the impact velocity could reduce the severe injury risk and fatality risk for impact velocities of 40 km/h or higher. Specifically, when the impact velocity was less than or equal to 30 km/h, the serious injury risks were less than 21% and the fatality risks were less than or equal to 1% for the above listed vehicle types. Therefore, if the Collision Damage Mitigation Braking System (CDMBS) equipped vehicles can perform its functions effectively so as to reduce the impact velocities, then cyclist injuries will likely be significantly reduced. Another purpose of this study is to assess the effect of wearing a helmet for protection of the cyclist’s head. Impact experiment results showed that the measured head injury criterion (HIC) with helmets are lower than that of head-form impactor without a helmet, reducing the HIC by 57%.
Matsui, Yasuhiro, Oikawa, Shoko
Wrap Around Distance WAD of Pedestrian and Bicyclists and Relevance as Influence Parameter for Head Injuries2015-01-14614/14/2015
During most pedestrian-vehicle crashes the car front impacts the pedestrian and the whole body wraps around the front shape of the car. This influences the head impact on the vehicle. Meanwhile the windscreen is a major impact point and tested in NCAP conditions. The severity of injuries is influenced by car impact speed; type of vehicle; stiffness and shape of the vehicle; nature of the front (such as the bumper height, bonnet height and length, windscreen frame); age and body height of the pedestrian; and standing position of the pedestrian relative to the vehicle front. The so called Wrap Around Distance WAD is one of the important measurements for the assessment of protection of pedestrians and of bicyclists as well because the kinematic of bicyclists is similar to that of pedestrians. For this study accidents of GIDAS were used to identify the importance of WAD for the resulting head injury severity of pedestrians and bicyclists. GIDAS (German In-Depth-Accident-Study) collects accidents as representative sample of the German accident situation based on in-depth-investigation. A total number of n=548 pedestrian and n=436 bicyclists suffered a head impact with the car collected within n=27,666 accidents with all kind of traffic participants and injured persons from the years 1999 to 2013 which are used for the study. Results: A significant influence respectively an increase of WAD by the driving speed of the bicycle cannot be found. The cumulative frequencies show, that WAD 1500 only covers about 8% of bicyclists but 18% of pedestrians. WAD 2100 covers about 51% of bicyclists and 74% of pedestrians. The WAD for pedestrian as measure of distance from the ground to the impact point of the head is dependent on the impact speed of the car. For lower speeds the front hood area is more often contacted and for higher speeds the windscreen. For Vans and off-road cars front hood impacts can only be seen in lower speed collisions. The WAD of bicyclists in general is higher than for pedestrians. The cumulative frequencies of body heights show that bicyclists are larger than pedestrians. The injury severity of the head (AIS head) is increasing with the age of the pedestrian or bicyclist. Only 6.9% of pedestrians and 3.3% of bicyclists in the age group of 16 to 25 years suffer head injuries of AIS 3+, in the age group over 55 years there are 19.7% of pedestrians and 16.1% of bicyclists. The WAD is not a significant influence parameter for the injury severity of the head. The WAD is only increasing slightly with higher injury severity of the head (AIS head). The WAD is a usable parameter for the correlating impact speed of the car. Age and impact speed of the car have highly significant influence (p<0.001) and body height has slightly significant influence on the injury severity of the head (p<0.05).
Otte, Dietmar
Economical Pedestrian Safety Equipment Countermeasures2015-01-14624/14/2015
Each year, more than 270,000 pedestrians lose their lives on the world's roads. Globally, pedestrians constitute 22% of all road traffic fatalities, and in some countries this proportion is as high as two thirds of all road traffic deaths. Millions of pedestrians are non-fatally injured and some of whom are left with permanent disabilities. These incidents cause much suffering and grief as well as economic hardship. To lower the rate of pedestrian injuries and fatalities, the Euro-Ncap committee adopted an overall impact star-grade system in 2009, making the pedestrian protection cut-off score required to obtain the best impact-star grade more stringent until 2016. It is very difficult to surpass the enhanced pedestrian cut-off score using past methods. In this paper, I determine the hood's worst-performing areas in terms of pedestrian protection by analyzing previous pedestrian test results. To improve performance at these areas, I developed a Damping latch & hinge and a 3-corner rearward pop-up system. I then proceeded to optimize the design of the hood inner panel, Long hood + Damping latch & hinge, and 3-corner rearward pop-up systems. Each system was put through a real vehicle pedestrian protection test to verify that it could improve pedestrian protection performance at the designated areas. As a result, we found that a 3-corner rearward pop-up system is the best method for pedestrian protection with consideration for cost, weight, and design.
Yang, Seung Jun
Improvement and Validation of the Lower Limb and the Pelvis for a Pedestrian Dummy2015-01-14714/14/2015
The evaluation of pedestrian safety performance of vehicles required by regulations and new car assessment programs (NCAPs) have been conducted. However, the behavior of a pedestrian in an actual car-pedestrian accident is complex. In order to investigate injuries to the pedestrian lower body, the biofidelity of the lower limb and the pelvis of a pedestrian dummy called the POLAR II had been improved in past studies to develop a prototype of the next generation dummy called the POLAR III. The biofidelity of the thigh and the leg of the POLAR III prototype has been evaluated by means of 3-point bending. However, the inertial properties of these parts still needed to be adjusted to match those of a human. The biofidelity of the pelvis of the POLAR III prototype has been evaluated in lateral compression. Although the experiment using PMHSs (Post Mortem Human Subjects) was conducted in dynamic condition, the dummy tests were performed only in quasi-static condition. Therefore, this study aimed to improve and further validate the lower limb and the pelvis of the pedestrian dummy to enhance assessment capabilities of injuries to these body regions. The femur and tibia solid shafts of the POLAR III prototype were modified to improve durability of the instrumentation. The modified thigh and leg of the POLAR III prototype consist of double-layered plastics shaft covered by the flesh. These parts were subjected to latero-medial 3-point bending. The isolated pelvis of the POLAR III prototype was subjected to dynamic lateral compression. The force-deflection curves of the modified leg, thigh and pelvis of the POLAR III prototype (except for iliac reaction force of pubic loading) were compared with those of the PMHS test results from a past study, and the biofidelity of these components was evaluated using the parameter proposed by a past study.
Asanuma, Hiroyuki, Takahashi, Yukou
Observation of the Lab-Scale Windeshield Impact Test and Simulation using the Time Dependent Dynamic Failure Criterion2015-01-05644/14/2015
In a car accident which is involving pedestrians, head injuries occur very frequently as the head of the pedestrian hits the windshield. The head injury criterion (HIC) obtained through the windshield impact test is used to evaluate the pedestrian injury, and car manufacturers are trying to meet the criterion by changing the design and/or materials.. However, there are some difficulties in the windshield impact test, e.g. a large scatter of the test data or windshield shape-dependent property of the test. These problems make it very difficult to obtain the meaningful results from single test and thus, tests should be executed several times. In this study, a lab-scale windshield impact test was performed using a modified instrumented dart impact (IDI) tester. Tests were carried out by switching test conditions such as the impact speed, the size of the head form and the specimen thickness. The key results such as acceleration and displacement curves of a head form, peak values from the acceleration curve, cracking modes, etc. were compared for various test conditions. In addition, the numerical simulation was carried out to correlate the lab-scale test results with full-scale windshield impact test, and the correlation between the lab-scale simulation result and full-scale simulation result of the earlier study is discussed.
Moon, Sung Wook, Kang, Byunghyun, Lim, Jaeyoung, Choi, Byoung-Ho
FE Driven Pedestrian Friendly Front End Design and Its Correlation with Physical Test2015-26-02121/14/2015
In the current competitive automobile market, with growing knowledge and concern for occupant and vulnerable road user safety, design & engineering of passenger cars in stipulated time is a challenge. As front styling is a crucial factor, early involvement of Computer Aided Engineering (CAE) through front loading helps reduce the product development time considerably with a pedestrian friendly engineered design. The present paper explains how initial inputs are given to styling & engineering teams during early stages of product development where availability of Computer Aided Design (CAD) data is minimal. Critical load paths were identified and shape of the front end was modified accordingly. Various locations of hinge mechanism were evaluated to reduce the severity of injury in the head impact zone. Sufficient gaps between the exterior surfaces and interior hard points were worked upon to reduce the impact values. Lower & upper energy absorbers for leg impact were proposed and tuned to meet the injury criteria. Stiffness of parts in the impact zone was varied and collapsible head lamp brackets were implemented to bring down the injury values. Optimization of the outer and inner bonnet was also done through a variation study. Thus by these concepts, a FE to CAD driven design approach instead of CAD to FE was implemented and the results were correlated with physical tests.’
Karani, Neerav, Malladi, Aditya, lingan Sr, Sridhar
Video Analysis and Analytical Modeling of Actual Vehicle/Pedestrian Collisions2014-01-04834/1/2014
Numerous mathematical models for reconstructing vehicle-pedestrian collisions have been developed over the years utilizing common sources of physical evidence. As sources of video data recording proliferate, new sources of physical evidence are now available in some cases. This paper presents an expanded methodology for analyzing video footage of actual pedestrian collisions, including both static and dynamic camera positions. Each video was analyzed using digitizing motion analysis software to quantify the pre-impact and post-impact trajectories and speeds of the vehicle, the pedestrian, and the camera position for each collision. The relationship between vehicle speed and pedestrian throw distance has frequently been used in collision reconstruction to answer questions regarding vehicle/pedestrian impacts. Several approaches to reconstructing vehicle/pedestrian collisions have been developed and published in the literature using equations derived from empirical models, principles of mechanics, or hybrid approaches. The empirical and hybrid categories of equations are based primarily on statistical analysis of staged crash tests with cadavers and dummies, or computer modeling simulations. Some prior studies have discussed vehicle/pedestrian reconstruction equations derived from staged tests or simulations and compared them to a small set of real-world event data. New data from actual video-captured vehicle-pedestrian collisions are presented as a comparison data set for further validation of previously published empirical and hybrid pedestrian reconstruction methodologies.
Rush, Thomas, Przybyla, Jay, Melcher, Daniel, Sax, Christian
Method of Selecting Test Scenarios for Pedestrian Forward Looking Pre-Collision System Evaluation2014-01-01634/1/2014
While the number of traffic fatalities as a whole continues to decline steadily over time, the number of pedestrian fatalities continues to rise (up 8% since 2009) and comprises a larger fraction of these fatalities. In 2011 there were 4,432 pedestrians killed and an estimated 69,000 pedestrian injuries [1]. A new generation of Pedestrian Pre-Collision Systems (PCS) is being introduced by car manufactures to mitigate pedestrian injuries and fatalities. In order to evaluate the performance of pedestrian PCS, The Transportation Active Safety Institute (TASI) at Indiana University-Purdue University Indianapolis is developing a set of test scenarios and procedures for evaluating the performance of pedestrian PCS with the support of the Collaborative Safety Research Center of Toyota. Pedestrian crashes are complex in that there are many aspects about location, driver behavior, and pedestrian behaviors that may have implications for the performance of the PCS. This complexity will generate far more scenarios than can be reasonably tested. This paper describes a test scenario selection process that uses not only the percentage importance of crash scenarios in terms of combinations of variables, but also ensures that individual variables are adequately represented in the chosen tests. The total number of test scenarios can be specified based on the percentage representation coverage according to the crash data or by the testing agency. The advantage of this method is that both important scenarios and important scenario variable values are guaranteed to be included in the set of test scenarios. The proposed method is demonstrated using GES and FARS pedestrian crash data for 2010 and 2011. The crash scenarios are described with variables that can be used for setting up vehicle tests, such as the pedestrian sizes, light conditions, pedestrian motion directions, pedestrian motion behavior/speeds, vehicle motion directions, and vehicle motion speeds. This method can also be used for creating a parsimonious set of test scenarios for other vehicle active safety features.
Chien, Stanley, Yi, Qiang, Good, David, Gholamjafari, Ali, Chen, Yaobin, Sherony, Rini
Finite Element Analysis of Pedestrian-City Car Collisions to Assist Design of Pedestrian Friendly Front Structure2014-01-20263/24/2014
Car-to-pedestrian collisions often cause serious injuries and deaths dramatically as pedestrians do not have any protection equipment. In order to design the front structure to be safer for pedestrians, it is necessary to understand kinematics and injury mechanisms of car-pedestrian collisions which can be obtained through the costly full-scale crash test of a dummy or a cadaver. Finite element simulations are an alternative mean which offer information of post-crash kinematics and injury mechanisms. This paper has presented finite element simulations of pedestrian-city car collisions by simulating legform impact test for assessment and validation. It has also been employed to simulate the full-scale pedestrian crash test. The post-crash kinematics and injury mechanisms of the pedestrian have been analysed. With the kinematics and injury information, the bumper beam of the front end of the car has been simply modified by introducing Al 6082 T6 to the bumper beam. The dynamics responses and injury parameters for head, chest, tibia and femur have been reduced significantly. These show that the car-to-pedestrian collision model can be employed to assist design and development of pedestrian friendly front structure of a vehicle.
Kongsakul, Wachirut, Carmai, Julaluk
Observations on Pedestrian Pre-Crash Reactions during Simulated Accidents2013-22-000611/11/2013
Pedestrian protection systems, both active and passive systems, are being introduced in the EU and Japan to comply with regulatory requirements. Their designs are specific and, in general, reflect an accident scenario of the pedestrian being struck on the side by a vehicle traveling at a maximum travel speed of 40 kph. The present study is an effort to quantify the effects of pedestrian reaction prior to an accident and identify characteristics that may help minimize or prevent the pedestrian to vehicle interaction. Accident situations were simulated with volunteers using a non-impacting methodology. Fifty one reactions from 23 volunteers of two age groups were observed. Most of the volunteers were found to run, step-back or stop in fright in a dangerous situation. Volunteer speed was an important parameter which could help in differentiating these reactions. Age related differences were also observed, both for reaction strategy and reaction times. While the majority of young subjects ran, elderly stopped as often as they run. Volunteers' posture at the time of impact was found to be highly variable irrespective of the type of reactions. The exception was when a volunteer stopped/braced in apparent fright and raised their arms to form a triangle covering their face and their head. Results of the present study may be helpful when selecting or evaluating the benefit of pedestrian safety strategies by allowing the inclusion of information about types of reaction, pedestrian speed, reaction time and age differences in the scenarios. In addition, pedestrian pre-crash postures and muscle activities could be utilized for evaluating/improving the passive safety systems and active models.
Soni, Anurag, Robert, Thomas, Rongiéras, Frédéric, Beillas, Philippe
Risks of Pedestrian Serious Injuries and Fatalities associated with Impact Velocities of Cars in Car-versus-pedestrian Accidents in Japan2013-22-000811/11/2013
The first purpose of this study is to clarify the relation between the car impact velocity and pedestrian injury severity or mortality risk. We investigated the frequency of serious injuries and fatalities of pedestrians using vehicle-pedestrian accident data from the database of the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. The vehicle types considered are sedans, minivans, and box vans (ordinary automobiles) and light passenger cars and light cargo vans (light automobiles). The results revealed that a 10-km/h reduction in impact velocity could mitigate severe pedestrian injuries in cases involving impact velocities of 40 km/h or more for the five vehicle types analyzed. Specifically, if the impact velocity was 30 km/h or less, the frequency of serious injuries was less than 27% and the frequency of fatalities was less than 5% for the five vehicle types. Therefore, if the collision damage mitigation braking system (CDMBS) that uses a sensor to detect pedestrians can effectively reduce the impact velocity for various vehicle types, pedestrian injuries will be greatly mitigated. The second purpose of this study is to identify the factors that affect injury risk. Impact experiments were conducted in which a sedan impacted against a pedestrian full-scale dummy at 40 km/h and a pedestrian headform impactor was impacted against a road surface. The results indicated that the risk of pedestrian serious injury was significantly affected by multiple impact conditions, such as the pedestrian height, car impact velocity, car frontal shape, and car stiffness in cases where the car impacted the pedestrian's head, the degrees of influence of which were driven by the vehicle impact velocity.
Matsui, Yasuhiro, Oikawa, Shoko, Ando, Kenichi
Features of Fatal Pedestrian Injuries in Vehicle-to-Pedestrian Accidents in Japan2013-01-07774/8/2013
The number of traffic deaths in Japan was 4,612 in 2011. Looking at the road accident fatalities, it revealed that pedestrians accounted for the highest number in 2011 (1,686, 36.6%). To develop safety countermeasures to decrease the severity of injuries and to reduce the number of deaths in traffic accidents, the detailed characteristics of pedestrian injury in vehicle-to-pedestrian crashes are necessary. The purpose of this study is to understand the scenarios of vehicle accidents in which pedestrians suffer fatal injuries. In the present study, we investigated the characteristics of pedestrian injuries in fatal crashes from accident analyses and compared them to head injury severity levels in impact tests against a road pavement and vehicle contact surfaces. In the accident analyses, we investigated the main body regions injured, that is, the most serious extent of injuries over the whole body of pedestrians by using macro vehicle-pedestrian accident data from database of the Institute for Traffic Accident Research and Data Analysis (ITARDA) of Japan. In comparing the differences in injury frequencies for various body regions between 1999 and 2009, it is noted that the frequencies of pedestrian fatalities due to head injuries were significantly reduced. The result indicated that even though head injuries were the most frequent cause of pedestrian fatalities in traffic accidents, the introduction of pedestrian head protection regulation in Japan in 2005 could be considered effective in reducing fatal head injuries. On the other hand, the frequencies of pedestrian fatalities due to hip injuries increased significantly in sedans, light passenger cars, and light cargo vans. Using the macro accident data in 2009, we investigated the frequency of pedestrian fatalities by gender, age group, vehicle travel speed, and fatal head injuries due to vehicle impacts or road pavement impacts. The results also indicated that the frequencies of female pedestrian fatalities due to hip injuries were significantly higher than those of males. Additionally, the results showed that the frequency of pedestrian fatalities due to hip injuries for the age group of over 65 years was significantly higher than that of the industrial age group (aged 13-59). Focusing on the frequency of pedestrian fatalities due to hip injuries in all age groups, vehicle travel speed appeared likely not to be an extremely important factor in increasing fatal hip injuries. In examining the differences in the frequency of fatal head injuries due to contacts with vehicles or road pavements, it is noted that injury frequency in crashes involving vehicles travelling at high speeds were significantly higher than those at lower speeds for pedestrians over 60 years of age. Focusing on head injury severity levels in impact tests against a road and vehicle surfaces using an adult pedestrian headform impactor, the impacts against a road pavement (HIC 6525) was considered to be more severe than those against vehicle front components with high stiffness (HIC from 2600 to 4032).
Matsui, Yasuhiro, Doi, Tsutomu, Oikawa, Shoko, Ando, Kenichi
In-house Design and Development of Pedestrian Protection Test Rig2013-26-00211/9/2013
Regulations on pedestrian safety have been introduced globally since the year 1990 and in India it will have to be met around the year 2016. Process of making vehicle compliant to this regulation requires rigorous design development and testing. Testing involves propelling head-forms (Child and Adult) on bonnet at 35 km/h and 40 km/h and leg-forms (Upper and Lower) on bumper at 40 km/h according to the different National / International / NCAP regulatory requirements A pedestrian protection test rig has been indigenously designed and developed in-house to perform pedestrian protection impact testing in-house. The paper describes the salient features of the pedestrian protection test rig, its functioning, operation and process of acquiring the data for determination of the values required by crash safety regulations.
Muhammed, Noufal, Abhishek, Kumar, Mohit, Tarwani, Mujawar, Zia
Research of the Relationship of Pedestrian Injury to Collision Speed, Car-type, Impact Location and Pedestrian Sizes using Human FE model (THUMS Version 4)2012-22-000710/29/2012
Injuries in car to pedestrian collisions are affected by various factors such as the vehicle body type, pedestrian body size and impact location as well as the collision speed. This study aimed to investigate the influence of such factors taking a Finite Element (FE) approach. A total of 72 collision cases were simulated using three different vehicle FE models (Sedan, SUV, Mini-Van), three different pedestrian FE models (AM50, AF05, AM95), assuming two different impact locations (center and the corner of the bumper) and at four different collision speeds (20, 30, 40 and 50 km/h). The impact kinematics and the responses of the pedestrian model were validated against those in the literature prior to the simulations. The relationship between the collision speed and the predicted occurrence of head and chest injuries was examined for each case, analyzing the impact kinematics of the pedestrian against the vehicle body and resultant loading to the head and the chest. Strain based indicators were used in the simulation model to estimate skeletal injury (bony fracture) and soft tissue (brain and internal organs) injury. The study results primarily showed that the injury risk became higher with the collision speed, but was also affected by the combination of the factors such as the pedestrian size and the impact location. The study also discussed the injury patterns and trends with respect to the factors examined. In all of the simulated conditions, the model did not predict any severe injury at a collision speed of 20 km/h.
Watanabe, Ryosuke, Katsuhara, Tadasuke, Miyazaki, Hiroshi, Kitagawa, Yuichi, Yasuki, Tsuyoshi
Different Factors Influencing Post-crash Pedestrian Kinematics2012-01-02714/16/2012
Pedestrian crashes are the most frequent cause of traffic-related fatalities worldwide. The high number of pedestrian accidents justifies more active research work on passive and active safety technology intended to mitigate pedestrian injuries. Post-impact pedestrian kinematics is complex and depends on various factors such as impact speed, height of the pedestrian, front-end profile of the striking vehicle and pedestrian posture, among others. The aim of this study is to investigate the main factors that determine post-crash pedestrian kinematics. The injury mechanism is also discussed. A detailed study of NASS-PCDS (National Automotive Sampling System - Pedestrian Crash Data Study, US, 1994-1998), showed that the vehicle-pedestrian interaction in frontal crashes can be categorized into four types: “Thrown forward”, “Wrapped position”, “Slid to windshield” and “Passed over vehicle”. A Principal Component Analysis (PCA) was performed and 11 independent factors were identified for study from a set of 26 variables, as defined in NASS-PCDS. Pedestrian-vehicle size ratio and the impact speed are the two most influential factors that determine post crash pedestrian kinematics. However, the standing posture of a taller pedestrian can also cause rotational movement around the local Z axis, leading to a face-up/down mode of head-face impact before falling on the hood. The findings from the NASS-PCDS study were also confirmed and verified with the help of numerical simulations performed using two modified JAMA human FE models. An adult model (male, 175cm and 72kg) and a properly scaled child model (6 years old, 120cm and 21kg) were effectively utilized to investigate the post-crash kinematics in different conditions.
Kawabe, Yoshiko, Asai, Toshiyuki, Murakami, Daisuke, Pal, Chinmoy, Okabe, Tomosaburo
Evaluation of Vehicle Systems Structural Durability Using PSD Based Fatigue Life Approach2012-01-09534/16/2012
In current competitive environment automobile industry is under heavy pressure to reduce time to market. First time right design is an important aspect to achieve the time and cost targets. CAE is a tool which helps designer to come up with first time right design. This also calls for high degree of confidence in CAE simulation results which can only be achieved by undertaking correlation exercises. In automobiles most of the structures are subjected to vibration from dynamic loads. All the dynamic road loads are random in nature and can be very easily expressed in terms of power spectral density functions. In the current scenario structural durability of the parts subjected to vibration is done partially through modal performance and partially though frequency response analysis. The only question that arises is what amplitude to use at what frequency and how to map all the accelerated tests dynamic load frequency spectrum to simulation domain. The paper describes a systematic and economical approach of mapping all the accelerated tests in a single PSD and further using it for vibration fatigue. In addition a good correlation of simulation results with the test data is presented for the PSD based approach.
Londhe, Abhijit, Kangde, Suhas, Moorthy, Narayana
Influence of Vehicle Front End Design on Pedestrian Lower Leg Performance for SUV Class Vehicle2011-01-00844/12/2011
Accident statistics shows pedestrian accident fatalities as one of the important concerns globally. In view of this, new test protocols for pedestrian safety have been drafted in regulation as well as in consumer group. Also as per new ENCAP requirements, pedestrian safety assessment is used as one of the four assessment criteria's (Adult protection, child safety, pedestrian safety, safety assist) in deciding the overall vehicle safety. Hence today importance of pedestrian safety is perceived as never before in vehicle development program. Basically pedestrian safety evaluation involves subsystem level (head form, upper leg form and lower leg form) impact tests representing human body parts, at specific region on test vehicle with injury limits to decide the severity of impact. In general these injuries are governed by vehicle styling, vehicle stiffness, hard points clearances from vehicle exterior like bonnet, bumper etc. For head impact, design parameter that mainly control the injury, like bonnet top stiffness design and under bonnet clearances remain valid for both passenger cars as well as for SUV's (Sport Utility Vehicles). Upper leg from impact test is not mandatory to be met in regulation and also difficult to meet in SUV class type vehicles as the location of impact is guided by bonnet leading edge which are quite high in case of SUV's because of vehicle stance. In case of lower leg test, injuries are mainly guided by front styling and bumper to hard point clearance. In SUV's as compared to passenger cars as the ground clearance from the ground is generally higher and vehicle styling is aggressive, controlling the injuries within the limits are quite challenging. This paper specifically discusses important design aspects on controlling the injuries of lower leg form for a SUV type vehicle to meet target requirements. This paper attempt to demonstrate the importance of vehicle front end styling, bumper system design, location of energy absorber, bumper profile, front end stiffness and limitation of bumper to hard point clearance in meeting the lower leg injuries.
Bhagat, Milind, Chalipat, Sujit, Ranade, Amod
Development of a Legform Impactor with 4-DOF Knee-Joint for Pedestrian Safety Assessment in Omni-Direction Impacts2011-01-00854/12/2011
The issue of car-to-pedestrian impact safety has received more and more attention. For leg protection, a legform impactor with 2 degrees-of-freedom (DOF) proposed by EEVC is required in current regulations for injury assessment, and the Japan Automobile Manufacturers Association Inc. (JAMA) and Japan Automobile Research Institute (JARI) have developed a more biofidelic pedestrian legform since 2000. However, studies show that those existing legforms may not be able to cover some car-to-pedestrian impact situations. This paper documents the development of a new pedestrian legform with 4 DOFs at the knee-joint. It can better represent the kinematics characteristics of human knee-joint, especially under loading conditions in omni-direction impacts. The design challenge is to solve the packaging problem, including design of the knee-joint mechanisms and layout of all the sensors in a limited space of the legform. Furthermore, reusable elements are used to achieve the joint stiffness requirements instead of destructive elements used in the EEVC 2-DOF legform. A prototype of the 4-DOF legform has been manufactured based on the design. The preliminary impact tests against bumper systems are also introduced in this paper.
Huang, Jun, Nie, Bingbing, Zeng, Long, Xia, Yong, Zhou, Qing
Design of “Lower Stiffener” for Controlling Pedestrian Lower Leg Injuries2011-26-01001/19/2011
Pedestrian protection is becoming an increasingly important aspect in vehicle safety development across the globe. The two primary focus areas are protection to the head and the lower leg of the pedestrian in impacts with motor vehicles. This paper discusses the protection aspects for lower leg in pedestrian impacts. The pedestrian lower leg injuries are measured in the form of deceleration; bend angle and knee shear as stated in regulations. Careful study indicates that a minimum of two load paths namely the upper load path (to support the femur) and the lower load path (to support tibia) are required to control the above stated injuries. Careful optimization is required to balance the stiffness on both the load paths. This paper further focuses on the component optimization to achieve necessary stiffness along the lower load path for injury control. One of the lower load path usually consists of the bumper, “lower stiffener” and its fixing system. Several iteration were carried out using CAE followed by physical tests with due considerations for design, performance, packaging and manufacturing constraints. The load path was optimized using correlated model and design was signed off successfully through full scale pedestrian lower legform tests
Karimullah, Shaikh, Gokhale, Ajit, Joshi, Samir, Chalipat, Sujit
ISO Headform Pedestrian Protection test results comparison at critical bonnet regions2010-36-023610/6/2010
Test Protocols for pedestrian head protection in a car pedestrian accident have been discussed for several Technical Communities in order to identify ideal boundary test conditions to evaluate injury limits. With the purpose to harmonize with final Global Technical Regulation 9 for Pedestrian Protection published by ECE in January 2009, European New Car Assessment Program (ENCAP) has changed their Child and Adult headform weight and geometry boundary test conditions. However 5 Kph remains as difference between both protocols. This work presents a comparative head impact test analysis for both headform at ENCAP and GTR#9 boundary test conditions when performed at critical bonnet regions.
Pereira, Ney Q.
Influence of free space from rigid under hood components to bonnet external surface in Pedestrian Injuries when impacted by vehicles2010-36-001310/6/2010
Hood development of internal structures in vehicles is an important alternative to minimize the injuries to pedestrians in case of a running over accident. In fact, according to Berg et al (2002), about 17% of head impacts occur on the hood. Moreover, according to Farooq and Schuster (2003), 62% of fatal injuries are caused by head trauma. This study focuses on evaluating the influence of free space between the hood and rigid components, considering cut out hood inner panel design, which is one of the geometries most commonly used by auto industries. The major advantage of this structure is its weight, leading, however, to small stiffness. Injuries to the head of a pedestrian is measured through a finite element model, in accordance with the European Committee for improvement in vehicle safety. There are several ways to measure the damage caused by the deceleration of the head. Here, the measure HIC (Head Injury Criteria), created by the NHTSA (National Highway Transport Safety Association) in 1971, is chosen, since it is still the most used and recommended method in the literature. Finally, the analyses of the numerical results lead to practical suggestions for auto industry.
Ferreira, Anderson Sirolli, Driemeier, Larissa
Design Style Influence on Pedestrian Leg Impacts2009-36-006710/6/2009
This paper presents a comparative analysis considering two different vehicle styling and a common energy absorber system. Based on the results, we will able to conclude about the Design Style influences on the pedestrian collisions because more than 70% of the pedestrian collision occurs in the front of the vehicle When we analyze pedestrian protection with focus on head impact, although the influence of hood geometries, material and thickness, generically a higher hood due to the under hood clearances helps on the results, but for leg impact, which is the influence on the results when a high vehicle is considered?
de Melo Baleki, Daniel, Ferreira, Anderson Sirolli
Development of Fender Attachment with Collapsible Brackets for Pedestrian Head Impact2009-36-009310/6/2009
In order to reduce the injuries during the vehicle- pedestrian collisions some alternatives for energy absorption have been applied. On average 27% of the head impacts occur on the hood and fenders and generally a great part of these are fatal injuries. For this reason some alternatives to hood development have been applied to reduce the injuries. Depends on Vehicle Style the impact could occur straight on the fenders, so for this cases we need to provide enough free deformation space between fender catwalk and upper rail to absorb the kinetic energy from Head impact because is physically necessary the deformation of the external surface for the other internal components to reduce the HPC values. Most of Automotive Manufactures has been applied the deformable brackets between fender and rail with purpose to deform during the head impact and absorb the kinetic energy. This paper presents a comparative analysis for alternatives to optimize the catwalk geometries, deformable brackets geometries and thickness to reduce the HPC, for inlaid hood concepts.
de Melo Baleki, Daniel, Ferreira, Anderson Sirolli
Estimation of Knee Ligament Injury Measures for a Pedestrian Dummy2009-01-12124/20/2009
In order to enhance understanding of pedestrian injury mechanisms, full-body pedestrian dummies have been developed in past studies. The goal of this study was to estimate knee ligament injury measures for a pedestrian dummy based on the correlation between dummy and human responses. For estimating knee ligament force of the dummy approximating the average ligament failure, finite element (FE) human and dummy knee joint models were subjected to dynamic 4-point bending. The estimated measures for the modified dummy knee ligaments were 3.0, 0.5 and 1.1 kN for the MCL, PCL and ACL, respectively. A full-body FE dummy model was subjected to impacts from a small sedan and a Sport Utility Vehicle (SUV) for validating the estimated force levels. The results showed that the estimated dummy knee ligament force levels predicted failure of human knee ligaments that is likely to take place first when leg fractures are not present in impacts from a small sedan and a SUV.
Takahashi, Yukou, Okamoto, Masayoshi, Akiyama, Akihiko, Kikuchi, Yuji
A Comparative Study Between China and IHRA for the Vehicle-Pedestrian Impact2009-01-12054/20/2009
A total of 200 detailed pedestrian accident cases of several areas in China were collected and analysed during last three years, the important information mainly include accident conditions, pedestrian information, human injury, vehicle injury sources, impact velocity, wrap around distance, and so on. The front shape of 37 passenger cars with high occupancy in domestic market involved in the accident cases were investigated and categorized into three groups: Sedan, SUV (Sport Utility Vehicle) and 1-Box (One Box Vehicle), so that the effect of vehicle front shapes on the pedestrian impact dynamics response and body injuries were studied. Then, the mathematical models for simulation of vehicle-pedestrian impact were developed using multi-body dynamics codes MADYMO to study response of pedestrian in vehicle-pedestrian impact. A parameter study was conducted under the conditions of different pedestrian size, impact velocities and vehicle shapes to determine and analyse the head impact condition which include HIC, head impact speed, head impact angle, WAD, head impact point, and so on. The research result was compared to that of IHRA (International Harmonized Research Activities). It was found that the characteristics of pedestrian accidents in China had many similarities between that of IHRA. The simulation result of head impact condition according to front shape of passenger cars in Chinese market was also similar to that of IHRA pedestrian working group. This study provides an effective basis of technical regulation for research on pedestrian test procedures and development of safer vehicle for pedestrian protection.
Huipeng, Chen, Lianxue, Fu, Heyue, Zheng
Efficient and Cost Effective Energy Absorbers for Automotive Bumper: A Novel Energy Absorber2009-26-00091/21/2009
During recent years, the development of new vehicles has to cope with continuously emerging requirements, implemented by new legislation and consumer test (eg. EuroNCAP) to insure occupant and pedestrian protection as well as new insurance classification test to improve vehicle damageability and repairability. These conflicting requirements have pose significant challenge to car manufacturers and designers to tune the vehicle front styling to meet pedestrian norm at the same time reduce damage to vehicle structure to minimize repair cost. Today Indian automotive OEM's are expanding their arms in global platform and need to design compliant vehicle front structure to meet these regulations requirements. Bumper is the first component that will come in contact during pedestrian or car-to-car impact and has a main role in damping the impact and minimize the injury. This paper explores injection molded thermoplastic energy absorber solution to meet pedestrian safety. Effective energy absorption, consistent impact performance for wide temperature range, functional integration makes thermoplastic as an ideal choice to designer. Thermoplastic energy absorber also gives higher design freedom to tune its stiffness based on the vehicle styling and regulation target. This paper presents thermoplastic energy absorber design at bumper level to meet lower leg form impact regulation. The effect of bumper height on the lower leg form kinematics and the design optimization to meet the pedestrian regulation target were discussed.
Kulkarni, Sandeep, Nagwanshi, Dhanendra, Bobba, Somasekhar
Influence of Impact Speed on Head and Brain Injury Outcome in Vulnerable Road User Impacts to the Car Hood2007-22-000710/29/2007
EuroNCAP and regulations in Europe and Japan evaluate the pedestrian protection performance of cars. The test methods are similar and they all have requirements for the passive protection of the hood area at a pedestrian to car impact speed of 40 km/h. In Europe, a proposal for a second phase of the regulation mandates a brake-assist system along with passive requirements. The system assists the driver in optimizing the braking performance during panic braking, resulting in activation only when the driver brakes sufficiently. In a European study this was estimated to occur in about 50% of pedestrian accidents. A future system for brake assistance will likely include automatic braking, in response to a pre-crash sensor, to avoid or mitigate injuries of vulnerable road users. An important question is whether these systems will provide sufficient protection, or if a parallel, passive pedestrian protection system will be necessary. This study investigated the influence of impact speed on head and brain injury risk, in impacts to the car hood. One car model was chosen and a rigid adjustable plate was mounted under the hood. Free-flying headform impacts were carried out at 20 and 30 km/h head impact velocities at different under-hood distances, 20 to 100 mm; and were compared to earlier tests at 40 km/h. The EEVC WG17 adult pedestrian headform was used for non-rotating tests and a Hybrid III adult 50th percentile head was used for rotational tests where linear and rotational acceleration was measured. Data from the rotational tests was used as input to a validated finite element model of the human head, the Wayne State University Head Injury Model (WSUHIM). The model was utilized to assess brain injury risk and potential injury mechanism in a pedestrian-hood impact. Although this study showed that it was not necessarily true that a lower HIC value reduced the risk for brain injury, it appeared, for the tested car model, under-hood distances of 60 mm in 20 km/h and 80 mm in 30 km/h reduced head injury values for both skull fractures and brain injuries. An earlier study showed that the corresponding value for a test speed of 40 km/h is 100 mm. A 10 km/h reduction in head impact velocity, as in automatic braking, allowed 20 mm less under-hood clearance with maintained head protection of the vulnerable road user.
Fredriksson, Rikard, Zhang, Liying, Boström, Ola, Yang, King
Characterization of the Rate-Dependent Mechanical Properties and Failure of Human Knee Ligaments2005-01-02934/11/2005
The structural properties of the four major human knee ligaments were investigated at different loading rates. Bone-ligament-bone specimens of the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments, obtained from post-mortem human donors, were tested in knee distraction loading in displacement control. All ligaments were tested in the anatomical position corresponding to a fully extended knee. The rate dependence of the structural response of the knee ligaments was investigated by applying loading-unloading cycles at a range of distraction rates. Ramps to failure were applied at knee distraction rates of 0.016 mm/s, 1.6 mm/s, or 1,600 mm/s. Averages and corridors were constructed for the force response and the failure point of the different ligaments and loading rates. The structural response of the knee ligaments was found to depend on the deformation rate, being both stiffer and more linear at high loading rates. This rate dependence was found to be more pronounced at high loading rates.
van Dommelen, J.A.W., Ivarsson, B.J., Minary Jolandan, M., Millington, S.A., Raut, M., Kerrigan, J.R., Crandall, J.R., Diduch, D. R.
Brightness to the Very Limit - Headlighting Sources With High Luminance - Mercury Free Xenon HID2005-01-10114/11/2005
In recent years environmental-friendly Mercury free Xenon HID lamp - D3 and D4 respectively with and without integrated igniter - were introduced in the automotive headlighting market. This market introduction was primarily driven by an increased concern for the environment by all stakeholders in car industry including the end-users. Furthermore, ordered by public authorities world wide, via new environmental legislation rules, Mercury free Xenon HID lamps will take over an important part of the Xenon HID market in due time. Within this perspective this paper will give an overview about technical backgrounds of Mercury free Xenon HID lamp performance. Next to light technical aspects the electrical interfaces between lamp and electronic driver are included. Furthermore, new developments in terms of satisfying carmakers requests on environmental aspects, electromagnetic compatibility and application flexibility will be discussed. The paper can be seen as a follow up of the previous publications in HID technology for headlighting. It will end up with an outlook of further progress in Mercury free Xenon HID lighting.
Tiesler-Wittig, Helmut, Postma, Pieter, Spinger, Benno
Assessment of Pelvis and Upper Leg Injury Risk in Car-Pedestrian Collisions: Comparison of Accident Statistics, Impactor Tests and a Human Body Finite Element Model2003-22-001910/27/2003
In this study, we first present a comparison between pelvis/upper leg injuries observed in real-world accidents as recorded in the database of the Medical University of Hanover, and the EEVC test results of corresponding cars as published by EuroNCAP. The fact that modern cars with rounded hood edges cause very few pelvis/upper leg injuries is discussed against the findings of the EEVC tests, where these cars do not perform significantly better than their older counterparts with sharper hood leading edges. This discrepancy could be due to the fact that the radius of the hood edge is not accounted for in the current version of the test protocol. In a second step, various impacts against several different simplified hood shapes were simulated using a detailed finite element model of a 50th percentile male pedestrian. The finite element model (THUMS) has been extensively validated against PMHS experiments in previous studies. The validated model affords detailed insight into pelvic and femoral deformations and loading patterns, and reveals, as expected, that the shape of the hood leading edge plays a critical role in the resulting biomechanical loading patterns. Based upon the results of this study, recommendations are offered for a more appropriate characterization of the hood shape with regard to pelvis/upper leg injury risk.
Snedeker, Jess G., Muser, Markus H., Walz, Felix H.
Foresight Vehicle: Using Accident Data to Develop Advanced Protection for Vulnerable Road Users (APVRU)2002-01-11223/4/2002
It is well known that certain road user groups, especially pedestrians and cyclists, are more vulnerable to fatal and serious injury than others. For example, in 1999, 32,552 road users were killed on EU roads, of which, 6,196 (19%) were pedestrians and 1,886 (6%) were cyclists. Safety systems designed to afford vulnerable road user groups greater protection require accident data in order to support and guide their development, and also to quantify their potential benefit. As part of a project developing a sensing system for cars capable of detecting, and reacting to, the presence of a vulnerable road user, accident data from the UK, Europe, and other international sources were employed to identify common accident and injury types. For example, international data sources showed that when considering pedestrian injuries greater than or equal to AIS 2 (AAAM, 1990) injuries, the main body regions injured were the legs, 36%, the head, 29%, the chest, 11%, and the abdomen or pelvis, 13%. Furthermore, for head injuries greater than or equal to AIS 2, the main injury contact points were identified as the windscreen glass, 44%, the top surface of the bonnet, 28%, and the windscreen frame or A-pillars, 18%. Approximately 62% of leg injuries were attributed to the front bumper, with 14% of femur injuries caused by the leading edge of the bonnet or wing. This information was important to identify the location of potential counter measures on the exterior of the vehicle. It was found that approximately 80% of fatal or serious pedestrian casualties in Great Britain occurred away from designated crossings, and that in approximately 15% of these cases, the pedestrian was obscured by parked cars prior to impact. Such information was important to determine a performance specification for the sensing technology.
McCarthy, M. G.
Conflict Simulation and Sensor Evaluation for the Advanced Protection of Vulnerable Road Users (APVRU) - A Foresight Vehicle Project2002-01-08263/4/2002
Modelling of conflicts between cars and pedestrians is presented in the paper. The model looks at how the velocities and distances change over the time between the pedestrian when first sensed and a potential impact, taking account of how the vehicle speed may be changing due to braking, wheel slip etc. Further work is outlined looking at the probability of conflict resolution behaviour by drivers and pedestrians. The paper also reviews current sensor technology appropriate for detecting pedestrians in front of a moving vehicle. A sensor system is required that responds to the road environment in real-time, and intelligently analyses the data so as to predict potential collisions and determine the nature of such collisions. A detection system combining radar detection with passive infrared detection and classification is proposed as a possible solution, meeting the requirements determined by conflict modelling and a review of the operating environment. Whilst these technologies have proven themselves in a variety of related applications further experimental work is proposed to demonstrate the feasibility of such a set-up.
Kerr, Daniel S., Parker, Graham A., McLundie, William M.
Revision and Validation of Vehicle/Pedestrian Collision Analysis Method2002-01-05503/4/2002
A comprehensive analysis method for assessing the vehicle impact speed in a vehicle/pedestrian collision was presented in an earlier publication (SAE #2000-01-0846) by the above authors [1]. This presented method provides a practical analytical approach for evaluating vehicle impact speed from the post-impact vehicle damage, pedestrian injuries and pedestrian throw distance. The applicability of this method to reconstructing real world vehicle/pedestrian collisions is examined. The results of this study indicate that the previously presented model can be used to assess a reasonable range for the vehicle impact speed in a vehicle/pedestrian collision. The regression model equations were revised to include the new data.
Toor, Amrit, Araszewski, Michael, Johal, Ravinder, Overgaard, Robert, Happer, Andrew
Development of a Reusable, Rate-Sensitive Abdomen for the Hybrid III Family of Dummies2001-22-000211/1/2001
The objective of this work was to develop a reusable, rate-sensitive dummy abdomen with abdominal injury assessment capability. The primary goal for the abdomen developed was to have good biofidelity in a variety of loading situations that might be encountered in an automotive collision. This paper presents a review of previous designs for crash dummy abdomens, a description of the development of the new abdomen, results of testing with the new abdomen and instrumentation, and suggestions for future work. The biomechanical response targets for the new abdomen were determined from tests of the mid abdomen done in a companion biomechanical study. The response of the abdominal insert is an aggregate response of the dummy’s entire abdominal area and does not address differences in upper versus lower abdominal response, solid versus hollow organs, or organ position or mobility. While the abdomen developed has demonstrated good biofidelity in rigid bar, seat belt and airbag loading situations, some work remains to be done before it can be used in crash testing.
Rouhana, Stephen W., Elhagediab, Ali M., Walbridge, Anthony, Hardy, Warren N., Schneider, Lawrence W.
Speed Limit in City Area and Improvement of Vehicle Front Design for Pedestrian Impact Protection-A Computer Simulation Study2001-06-02276/4/2001
This paper presented a part of results from an ongoing project for pedestrian protection, which is carried out at Chalmers University of Technology in Sweden. A validated pedestrian mathematical model was used in this study to simulate vehicle-pedestrian impacts. A large number of simulations have been carried out with various parameters. The injury-related parameters concerning head, chest, pelvis and lower extremities were calculated to evaluate the effect of impact speed and vehicle front structure on the risk of pedestrian injuries. The effect of following vehicle parameters was studied: stiffness of bumper, hood edge, hood top, windscreen frame, and shape of vehicle front structures. A parameter study was conducted by modelling vehicle-pedestrian impacts with various sizes of cars, mini vans, and light trucks. This choice represents the trends of new vehicle fleet and their frequency of involvement in real world accidents. The mechanical properties of the vehicle front were based on the available data from EURO NCAP tests, and from published literature. Based on the results from the simulation study, possible benefits from speed control in urban area can be assessed. As the impact speed decreases from the 40 to 30 km/h, the probability of severe head injury will decrease from 50% to lower than 25%. The influences of the various compliance and geometric parameters of vehicle front are analyzed. The most significant parameters to pedestrian impact protection are clarified, especially for head and lower extremities. A procedure in new vehicle-front design is presented, which can lead to a design guideline of safer vehicles for pedestrians. Furthermore, gaps in pedestrian protection are identified, and the research priorities should be focused on the adult head and lower extremities and child head and thorax injuries.
Yang, Jikuang, Liu, Xuejun, L\arvsund, Per, Tingvall, Claes, Lie, Anders, Larsson, Peter, Lekander, Thomas
Pedestrian injury projection in Australia if vehicles achieved a higher pedestrian star rating2001-06-01866/4/2001
Pedestrian tests are now included in vehicle crash testing carried out by Australian NCAP to the same procedure as EuroNCAP. Australia has a five year average of 338 pedestrians killed each year amounting to 18% of the total road toll, with many more admitted to hospital. Test data from EuroNCAP Pedestrian tests have been used to indicate the present likelihood of serious head injury to struck pedestrians. Predictions on serious head injury rates are made if the Australian vehicle fleet achieved a minimum of 3 star pedestrian rating or better by the EuroNCAP test and assessment protocols. Estimates of the number of years for the fleet to achieve a higher level of performance are made. Some locations of vehicle bonnet sites that cause high HIC readings are made for designers to take note of.
Coxon, Christopher G. M.
BIOFIDELITY OF TEST DEVICES AND VALIDITY OF INJURY CRITERIA FOR EVALUATING KNEE INJURIES TO PEDESTRIANS2001-06-00216/4/2001
In the current test procedure proposed by the European Enhanced Vehicle-safety Committee (EEVC)/WG17 for evaluating leg injuries to pedestrians, a legform impactor with a rigid bony structure is used. The risk of damages to knee ligaments is evaluated with the shearing displacement and the bending angle at the knee joint. A recent study has focused on evaluating biofidelity of the legform. However, it was not possible to obtain a local deformation at the knee joint from published experiments with Post Mortem Human Subjects (PMHSs). In addition, past PMHS experiments have suggested that the height of a bumper significantly affects the risk of ligamentous damages. In this study, three kinds of finite element models were used in order to investigate the relationship between the bumper height and the shearing displacement / bending angle of the knee; 1) a legform impactor with a rigid bony structure, 2) a recently developed pedestrian dummy (Polar) with both a flexible tibia and a biofidelic knee joint structure, 3) a human lower limb. By utilizing the human model, a local deformation at the knee joint could be obtained. The model for the legform impactor and the pedestrian dummy have been validated against experiments with an actual car and in component level, respectively. The human lower limb model has been validated against published PMHS experiments. The result of a parameter study with these models in a range of bumper heights showed that the dynamic response of the dummy model is quite similar to that of the human model. In addition, it was found that the mass of the upper body significantly affects the bending angle of the knee. A geometric analysis of the knee joint was also performed to obtain tensile strains of four principal knee ligaments as a function of both the shearing displacement and the bending angle. The result suggested that the shearing displacement and the bending angle should be considered in combination when developing an injury criteria for knee ligaments.
Takahashi, Yukou, Kikuchi, Yuji
DEVELOPMENT OF A FINITE ELEMENT MODEL OF THE TOTAL HUMAN MODEL FOR SAFETY (THUMS) AND APPLICATION TO CAR-PEDESTRIAN IMPACTS2001-06-00546/4/2001
“THUMS (Total Human Model for Safety)”, as shown in Figure 1, is a finite element model of a human body developed to study various injury mechanisms, and is used as a substitute for the crash test dummies used for car occupants and pedestrians. “THUMS” is designed so that the whole body can be deformed and modeled in detail up to an AM50%ile size. In this paper, “THUMS” is used as a pedestrian model and it is validated through the verification of pedestrian’s whole body kinematics and lower extremity injuries. The simulation results are in good agreement with car-pedestrian impact test results using cadavers.
Maeno, Tomoyuki, Hasegawa, Junji
SUMMARY OF IHRA PEDESTRIAN SAFETY WG ACTIVITIES – PROPOSED TEST METHODS TO EVALUATE PEDESTRIAN PROTECTION AFORDED BY PASSENGER CARS2001-06-01366/4/2001
The IHRA Pedestrian Working Group has conducted investigation and analysis on the current status of pedestrian accidents in the IHRA member countries. We collected the accident data that occurred by 1999, then unified the formats of the accident data and established a dataset that makes it possible to make comparison with each other. According to the current status of pedestrian accidents, three parts of the pedestrian’s body have the highest priority for protection, the child and adult heads, and the adult lower leg/knee. As for the motor vehicle, we determined which particular parts of the motor vehicle were involved, which pedestrian body parts they injured and the severity of the injuries, and analyzed the effect of their shapes, corresponding to the items above. It was decided that the test methods should be for motor vehicles for passenger use but not buses and coaches. The shapes of passenger cars were investigated and categorized by three groups, Sedan, SUV (Sport Utility Vehicle) and 1-Box (One Box Vehicle), so that the effects of these vehicle shapes could be studied with computer simulations. The simulations to date have focused on the head impact speed, head impact angle, head effective mass, and the Wrap Around Distance to the head impact point (WAD). We decided to adopt the sub-system methods and to establish specifications for impactors for each sub-system. That is, three subsystem test procedures (adult headform, child headform and legform impact tests) were proposed in high priority identified in the analysis of pedestrian accidents in the IHRA member countries. The pedestrian test procedures proposed and investigated by the experts of IHRA member countries may in the future provide a basis of technical regulations, however, it was recognized that considerable research and development was required to refine the test procedure. It was deemed necessary to conduct validation study of the test procedures through actual tests using sample vehicles and to explore the car feasibility level prior to the use of the test methods in legislation.
Mizuno, Yoshiuki, Ishikawa, Hirotoshi
IMPROVEMENTS TO PEDESTRIAN PROTECTION AS EXEMPLIFIED ON A STANDARD-SIZED CAR2001-06-01436/4/2001
Despite the steadily declining number of pedestrian fatalities and injuries in most European countries during the recent decades, pedestrian protection is still of great importance in the European Union as well as in Germany. This is because they still constitute a large proportion of road user casualties and are more likely to suffer serious and fatal injuries than most other road users. In 1999 only car occupants suffered more fatal injuries than pedestrians in Germany. In December 1998, EEVC WG 17 completed their review and updating of the EEVC WG10 pedestrian test procedure that made it possible to evaluate the protection afforded to pedestrians by the front of passenger cars in an accident. Within the scope of this procedure four different impactors are used representing those parts of the body, which are injured very often and/or very seriously in vehicle-pedestrian-collisions. In a project executed by ika and BASt a small family car was tested according to the EEVC WG 17 test procedure. Afterwards modifications to the car were carried out in order to improve the pedestrian protection provided by the vehicle design. There were certain restrictions placed on the level of modifications undertaken, e.g. only minor modifications to vehicle styling and to the vehicle structures, which provide passenger protection. The redesigned vehicle was tested again using the WG17 test procedure. The test results of the modified vehicle were compared with those of the standard vehicle and evaluated. The results show that considered measures for pedestrian protection in many areas of the vehicle front structure and the use of innovative techniques can lead to a significant reduction of the loads of pedestrians at an acceptable expense.
Kalliske, Ingo, Friesen, Flavio
A STUDY OF THE UPPER LEG COMPONENT TESTS COMPARED WITH PEDESTRIAN DUMMY TESTS2001-06-02356/4/2001
The upper leg component test proposed by EEVC WG17 is one of the tools for the evaluation of upper leg injuries in pedestrian accidents. Meeting the injury criteria set by EEVC for the upper legform impact test is one of the biggest challenges we can find in the reports. This problem was studied in previous papers using simulation models or reconstruction of pedestrian accidents. The POLAR pedestrian dummy was constructed by HONDA R&D and GESAC INC., and some crash tests were conducted with it. The object of this study is to compare EEVC WG17 upper legform impact test conditions for utility vehicles with the full dummy test results. To reconstruct the deformation resulting from tests using the POLAR, the impact energy for the EEVC upper legform impact test should be decreased. Even the upper limit of 700J is too high. Accident data analysis shows that the pelvis is the body part injured by the bonnet leading edge of the utility vehicle. So the impact force should be mainly considered for the evaluation of the bonnet leading edge performance.
Okamoto, Yutaka, Akiyama, Akihiko, Okamoto, Masayoshi, Kikuchi, Yuji
Analysis of a Front Integration Frame2001-01-07593/5/2001
The purpose of this article is to provide a methodology in analyzing the Front Integration Frame (FIF). Since this structure is a key component to closing out the Body in White, one needs to analyze this structure as a singular and integral part of the front body structure. A Design Verification and Report is a common methodology used to prove out a design before marketing. The more computer simulations that are adopted, in the analysis of the FIF before prototyping, the less revisions will be needed due to design failure.
Cottrell, Paul Edward
Development and Validation of the Finite Element Model for the Human Lower Limb of Pedestrians2000-01-SC2211/1/2000
An impact test procedure with a legform addressing lower limb injuries in car-pedestrian accidents has been proposed by EEVC/WG17. Although a high frequency of lower limb fractures is observed in recent accident data, this test procedure assesses knee injuries with a focus on trauma to the ligamentous structures. The goal of this study is to establish a methodology to understand injury mechanisms of both ligamentous damages and bone fractures in car-pedestrian accidents. A finite element (FE) model of the human lower limb was developed using PAM-CRASH™. The commercially available H-Dummy™ lower limb model developed by Nihon ESI for a seated position was modified to represent the standing posture of pedestrians. Mechanical properties for both bony structures and knee ligaments were determined from our extensive literature survey, and were carefully implemented in the model considering their strain rate dependency in order to simulate the dynamic response of the lower limb accurately. The element elimination option in PAM-CRASH™ was used to simulate both bone fractures and ligamentous ruptures. Bone models were validated against test results obtained from literature in both static and dynamic conditions. The dynamic response of the knee joint was validated against the response corridors from a series of experiments with Post-Mortem Human Subject (PMHS) presented in the literature. In addition, the lower limb model was validated against published experiments with isolated lower limbs subjected less motorized countries. The lower limb is one of the most frequently injured body region in severe injuries to pedestrians mainly due to direct impact from a vehicle front. According to the Pedestrian Crash Data Study (PCDS) database by NHTSA, lower limb injuries are the second most frequent region accounting for 26% of all AIS3+ injuries in pedestrians. Lower limb injuries are also very costly and often lead to long-term disability or impairment. The validated FE lower limb model was integrated with an upper body model with rigid segments to obtain a full-body pedestrian model. Computer simulations using both the pedestrian model and a FE model for the car front were conducted to reconstruct a published car-pedestrian impact test with PMHS. Leg fracture observed in the experiment was reproduced from the FE car- pedestrian model. The developed FE model can be used as an effective tool to investigate injury mechanisms of the lower limb in car-pedestrian accidents.
Takahashi, Yukou, Kikuchi, Yuji, Konosu, Atsuhiro, Ishikawa, Hirotoshi
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