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Accident data show that the head and the chest are the most frequently injured body regions in side impact fatal accidents. Curtain side air bag (CSA) and thorax side air bag (SAB) have been installed by manufacturers for the protection devices for these injuries. In this research, first we studied the recent side impact accident data in Japan and verified that the head and chest continued to be the most frequently injured body regions in fatal accidents. Second, we studied the occupant seating postures in vehicles on the roads, and found from the vehicle's side view that the head location of 56% of the drivers was in line or overlapped with the vehicle's B-pillar. This observation suggests that in side collisions head injuries may occur frequently due to contacts with the B-pillar. Third, we conducted a side impact test series for struck vehicles with and without CSA and SAB.

Accident data show that the injury risks to children seated in child restraint systems (CRSs) are higher in side collisions than any other type of collision. To investigate child injury in the CRS in a side impact, it is necessary to understand the occupant responses in car-to-car crash tests. In this research, a series of full car side impact tests based on the ECE R95 test procedure was conducted. In the vehicle's struck-side rear seat location, a Q3s three-year-old child dummy was seated in a forward facing (FF) CRS, and a CRABI six-month-old (6MO) infant dummy was seated in a rear facing (RF) CRS and also was placed in car-bed restraint. In the non-struck side rear seat location, the RF CRSs also were installed. In addition to testing the CRSs installed by a seatbelt, an ISOFIX FF CRS and an ISOFIX RF CRS were tested. For the evaluations, occupant kinematic behavior and injury measures were compared.

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.

The main objective of this study is to determine the damage tolerance and to describe the damage mechanisms of the extended human knee when it is exposed to lateral impact loads in pedestrian accidents, particularly those that occur at high velocity. An experimental method for assessing the damage tolerance of the knee region to loads acting at the extended lower extremity was developed. In-Vitro experiments with human subjects were conducted where only the purest possible shearing deformation or the purest possible bending deformation affected the knee region at the time. Ten experiments at a velocity level of 40 km/h were performed in a shearing and a bending setup, respectively. The peak values of the shearing force and the bending moment related to the damage of knee ligaments and bone fractures were calculated at knee joint level. Damages were assessed by dissecting the lower extremity.

In the current Japanese and European side impact regulation, occupant protection is evaluated based on anthropomorphic test device (hereafter referred to as the more commonly used term “dummy”) measurements recorded in a stationary car impacted by a moving deformable barrier (MDB). In order to validate and improve the side impact test procedures of the regulation and the associated new car assessment program, it is necessary to compare the side impact test procedure with car-to-car side impact tests conducted in various conditions. In this research, a series of car-to-car side impact tests using a small sedan as the target vehicle was conducted as follows: (1) A striking car impacted against the stationary car at 50 km/h at an impact angle of 90 degrees. (2) A 1BOX vehicle impacted the stationary car at 50 km/h at an impact angle of 90 degrees. (3) Both cars were moving, and the striking car impacted the struck car at an impact angle of 90 degrees.

The main objective of the present study is to determine experimentally the injury patterns and response of the human thigh in lateral impacts simulating more closely the real impact conditions in car-pedestrian accidents. We conducted in-vitro experiments on thirteen thighs of eight completely intact Post Mortem Human Subjects (PMHSs). The thigh was hit by a ram at a speed of 35 km/h at the mid-shaft of the femur in each completely intact PMHS. Since the effect of cumulative injuries should be avoided, each thigh was impacted only once. Three impact energies were used; 450J, 600J and 700J. The PMHS motion was not constrained so as to simulate the walking posture of a pedestrian. We analyzed the peak values of the impact force of the ram and the femur acceleration. Injury was assessed by dissecting the lower extremities.

The goal of the present study was to develop a new legform impactor that accurately represents both the impact force (i.e., force between the leg and impacting mass)and leg kinematics in lateral impacts simulating car-pedestrian accidents. In its development we utilized the knee joint of the pedestrian dummy called Polar-2 (HONDA R&D) in which the cruciate and collateral ligaments are represented by means of springs and cables, the geometry of the femoral condyles is simplified using ellipsoidal surfaces, and the tibial meniscus is represented by an elastomeric pad. The impactor was evaluated by comparing its responses with published experimental results obtained using postmortem human subjects (PMHS). The evaluation was done under two conditions: 1)impact point near the ankle area (bending tests),and 2)impact point 84 mm below the knee joint center (shearing tests). Two impact speeds were used: 5.56 m/s and 11.11 m/s.

Analysis of the results of previous simulations of pedestrian collision performed with different commercial dummies have indicated that test results do not always correspond with observations in simulations with cadavers. It seems that determining the risk of injury to pedestrians from these dummy tests may be very difficult. To study injury-related parameters in connection with mechanical dummies, 21 crash tests were performed at the Institute of Forensic Medicine at the Medical University of Hannover. Various front structures and velocities of vehicles were simulated. Two measuring tools were used for verification: a standard Hybrid II dummy, and the lower part of a Rotationally Symmetrical Pedestrian Dummy (RSPD) with no representation of the upper body. RSPD was previous developed at the Department of Injury Prevention at Chalmers University in Göteborg.

A 3D pedestrian knee joint model was developed as a first step in a new description of the whole pedestrian body for computer simulations. The model was made to achieve better correlation with the results from previous tests with biological material. The model of the knee joint includes the articular surfaces, ligaments and capsule represented by the ellipsoid and plane elements as well as the spring-damping elements, respectively. The mechanical properties of the knee joint were based on available biomechanical data. To verify the new developed model with results from tests with biological material previously performed at the Department of Injury Prevention, Chalmers University of Technology, the computer simulations were carried out with the model of the knee joint using the MADYMO 3D program.

Numerous studies of pelvic tolerance to lateral impact aimed at protecting car occupants have been conducted on Post Mortem Human Subjects (PMHSs) in a sitting posture. However, it remains unclear whether or not the results of these studies are relevant when evaluating the injury risk to walking pedestrians impacted by a car. Therefore, the first objective of the present study is to determine the injury tolerance and to describe the injury mechanisms of the human pelvis in lateral impacts simulating car-pedestrian accidents. The second objective is to obtain data for validation of mathematical models of the pelvis. In-vitro experiments were conducted on twelve PMHSs in simulated standing position. The trochanter of each PMHS was hit by a ram at speed of 32 km/h, and the pelvic motion was constrained by a bolt. This type of pelvic constraint is difficult to simulate in mathematical models.

The shearing and bending injury mechanisms of the knee joint are recognised as two important injury mechanisms associated with car-pedestrian crash accidents. A study on shearing and bending response of the knee joint to a lateral impact loading was conducted with a 3D multibody system model of the lower extremity. The model consists of foot, leg and thigh with concentrated upper body mass. The body elements are connected by joints, including an anatomical knee joint unit that consists of the femur condyles, tibia condyles and tibia1 intercondylar eminence as well as ligaments. The biomechanical properties of the model were derived from literature data. The model was used to simulate two series of previously performed experiments with lower extremity specimens at lateral impact speeds of 15 and 20 km/h.

Injuries to motorcyclists lead to permanent disability more often than injuries to car occupants (10 percent versus 6 percent). The use of helmets has decreased the risk of head injuries. Other injuries leading to permanent disability are currently concentrated on the extremities (about 70 percent). Almost all are due to fractures located in joints where knees, elbows, shoulders, and ankles are the modest common spots. In a study based on 200 motorcycle accidents, it was shown the existing protective clothing had no effect on the incidence of fractures to knees, elbows, and shoulders. Based on that knowledge, a new motorcycle suit was constructed. The main goal was to find a shock-absorbing material to protect knees, elbows, and shoulders in an accident. Confor Foam, a medium-density urethane foam, was tested and found to possess relevant characteristics.

The level at which forces are transmitted from the striking vehicle in side impacts may influence the response of the struck car in several different ways. A better contact between the front bumper of the striking and the sill area of the struck car has been considered to be desirable in this respect. In side impacts, the most frequent direction of the impact is from 3 and 9 o'clock, while the direction of the forces is usually from 2 and 10 o'clock due to the velocity of the struck car. A European car and the EEVC moving deformable barrier have, therefore, been used in a crabbed mode to study the problem of load transfer at different levels above the ground. Volvo and Saab cars were used as targets in 55 km/h side impact with an APROD-81 side impact dummy placed on the struck side in the front seat. The results indicate that a difference in the level at which the loads were applied could influence the deformations, the kinematics of the struck cars, and the loading of the occupant.

Improvement of pedestrian safety is considered a priority in crash injury protection. Dummies, however, are not able to give a humanlike and repeatable impact response in pedestrian tests. The Biomechanical Laboratory of ONSER in France and the Department of Traffic Safety of Chalmers University in Götheborg, Sweden have designed a new dummy for pedestrian testing. The dummy is designed according to the latest available anthropometric and biomechanical data. Its symmetry around the vertical axis allows repeatability for the kinematic and injury parameters. It allows a measurement of uncommon biomechanical parameters related to injury mechanisms. Its leg is instrumented to determine the distribution of forces and momenta applied to the leg.

The main objective of this study is to determine the damage tolerance and describe the damage mechanisms of the extended human knee when it is exposed to lateral impact loads in car-pedestrian accidents, particularly those that occur at a low velocity (20 km/h), and compare the results with those obtained at a high velocity (40 km/h). In-vitro experiments with human subjects were conducted where only the purest possible shearing deformation or the purest possible bending deformation affected the knee region at the time. Five experiments were performed in the shearing setup and another five in bending setup. The peak values of the shearing force and the bending moment related to the damage of knee ligaments and bone fractures were calculated at the knee joint level. Damages were assessed by dissecting the lower extremity. When the knee joint was exposed to the “purest possible shearing deformation”, the common initial damagemechanism was ligament damage related to ACL (60% of cases).

The objective of this research is to clarify the significant factors causing AIS 2+ femur or pelvis pedestrian injury, and to understand whether the current EEVC upper legform test reflects real world pedestrian accidents. An in-depth case study was conducted using the selected 82 pedestrian accident cases from 1987 to 1997 in the data base of Japan Automobile Research Institute (JARI) and Institute for Traffic Accident Research and Data Analysis (ITARDA). The results indicate the significant factors were the bonnet leading edge height, the vehicle registration year and the pedestrian age. The bumper lead was not a significant factor. However, the test condition of the EEVC upper legform test depends on the bumper lead and the bonnet leading edge height. The current test condition of the EEVC upper legform test should be reconsidered excluding the bumper lead.

SAE International defines six levels of autonomous driving system, four of which include a change of control from the system to the driver in certain conditions. When vehicle control changes from the system to a human driver, a safe transition time is necessary. The present study focuses on level 3 automation, in which the system controls driving in ordinary conditions, but the human driver is expected to intervene in emergency situations. The aim of this study was to investigate the relationship between driver posture and transition time. Driver posture included four components: backrest angle, seat position, foot position, and arm position. These were adjusted to investigate a total of 30 posture patterns. In addition, the situation in which the driver was not watching the road, but instead using a tablet computer was investigated. The driver’s braking and steering reaction times were measured for a highway-driving scenario in which a truck dropped cargo in front of the vehicle.

Fatal injuries suffered by cyclists in vehicle-versus-cyclist accidents are investigated to provide information for the introduction of safety countermeasures. We analyzed characteristics of cyclist injuries in real fatal accidents and compared them with severity levels of head injury in impact tests against a road surface. In the accident analyses, we investigated the main body regions whose injuries led to fatalities using a macro vehicle-cyclist accident database of the Institute for Traffic Accident Research and Data Analysis of Japan. Using data from 2009 to 2013, we investigated the frequency of cyclist fatalities by gender, age group, vehicle speed, and the source of fatal head injury (impact with the vehicle or road surface). Results indicated that head injuries are the most common cause of cyclist fatalities in car-cyclist accidents.

In nonfatal car-pedestrian accidents, lower extremities are the most commonly injured body parts. The test device used to evaluate the car-front aggressiveness regarding the risk of these injuries is a legform impactor. Injury-related factors causing AIS 2+ injury in the human lower leg when exposed to a lateral impact representing a pedestrian accident should be identified. One of the test devices commonly used to evaluate the risk is the legform impactor developed by the Transport Research Laboratory (TRL). However, information about the biofidelity of this impactor and leg injury tolerance curves is lacking.

This study aims to clarify the relation between axonal deformation and the onset of axonal injury. Firstly, to examine the influence of strain rate on the threshold for axonal injury, cultured neurons were subjected to 12 types of stretching (strains were 0.10, 0.15, and 0.20 and strain rates were 10, 30, 50, and 70 s-1). The formation of axonal swellings and bulbs increased significantly at strain rates of 50 and 30 s-1 with strains of 0.15 and 0.20, respectively, even though those formations did not depend on strain rates in cultures exposed to a strain of 0.10. Then, to examine the influence of the strain along an axon on axonal injury, swellings were measured at every axonal angle in the stretching direction. The axons that were parallel to stretching direction were injured the most. Finally, we proposed an experimental model that subjected an axon to more accurate strain.