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Occupant protection performance in frontal crashes has been developed and assessed for mainly front seat occupants over many years, and in recent years protection of rear seat occupants has also been extensively discussed. Unlike the front seats, the rear seats are often occupied by children seated in rear- facing or forward - facing child restraint systems, or booster seats. In the European New Car Assessment Program (NCAP), child occupant protection assessments using 18-month-old and 3-year-old test dummies in the rear seat are already being conducted. In addition, studies are under way concerning the development and introduction of test dummies of 6-year-old (6YO) and 10.5-year-old children. In this study, we focused on 6-year-old children sitting in belt-positioning booster seats. Offset frontal crash tests were conducted using two types of test dummies, a Hybrid III 6YO and a 6YO Q-series dummy (Q6), positioned in the rear seat.

An analysis of real-world traffic accidents shows that vehicle-to-vehicle collisions at an oblique impact angle account for 80% of all frontal accidents. It is thought that twisting of the upper body and legs of occupants occurs in this type of accident because of rotation of the vehicles at the time of impact. Such twisting of an occupant's restrained upper body might affect the effectiveness of occupant restraint systems, for example, an airbag may strike the head or thorax area at an oblique angle. The mechanism of upper body twisting and the possible effect of such twisting behavior on the performance of restraint systems were analyzed. Frontal sled tests were conducted to compare the response of the Hybrid III dummy and that of the next-generation THOR-FT dummy featuring improved biofidelity. MADYMO simulation models of the Hybrid III dummy and the THOR Alpha dummy were also used to examine occupant behavior in frontal impacts.

The causes of injuries suffered by drivers in “small-overlap frontal crashes” (SOFC) were examined. These crashes were defined as ones in which vehicles are loaded outside their longitudinal side members. SOFC accident data sets stored in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) database were investigated. Percentages of cases sustaining injury to each body region of drivers were calculated, and the differences between the percentages of injury by body region were examined. To investigate the injury mechanisms, SOFC tests with two types of rigid barrier were then conducted. Injury values in each body region were analyzed to validate the reproducibility of SOFC test as a relevant test.

A new highly biofidelic side impact dummy, the WorldSID 50th percentile male, has been developed under the supervision of the International Organization for Standardization in order to harmonize a number of existing side impact dummies in one single dummy. Momentum is growing for using the WorldSID in safety tests in the EU and the US. In the present study, two Euro-NCAP pole side impact tests were conducted to compare ES-2 and WorldSID responses in a mid-size SUV with respective seating positions as stipulated in the Euro-NCAP test conditions and fitted with the same side airbag. It was found that, compared with ES-2, the chest, abdomen and pelvis accelerations of WorldSID are more sensitive to variation in the applied external load transmitted by the deployed side airbag and door intrusion.

Recently, frontal impact compatibility is discussed internationally and various procedures to assess compatibility and various measures to improve compatibility have been proposed. Considering the above, car-to-car tests between a heavy car and a light car were conducted to clarify the effect of homogenizing the front structure on compatibility. Then correlation between the results of the barrier impact tests proposed as the procedures to assess compatibility and the car-to-car test results and the requirements for the assessment procedure were discussed.

In a typical passenger car-to-pedestrian collision, it is noted that the pedestrian’s body rotates after the initial contact with the hood leading edge. Consequently, the head often crashes into a stiff part of the car body, resulting in serious or life-threatening head injuries. Therefore, to reduce pedestrian fatalities, it is important to improve vehicle structures so as to mitigate head injuries. Front fenders are one example of such stiff body parts with small impact energy absorption capability. This paper reports on the development of a new front fender structure designed to mitigate pedestrian head injuries in passenger car-to-pedestrian collisions. The new structure is characterized by fender supporting brackets that incorporate a break-off mechanism in the riveted joints between the fender and brackets.

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”.

This study proposes an impact-triggered automatic braking system as a potential safety improvement based on the characteristics of the Multiple Impact Crashes (MICs). The system activates with a signal of airbag deployment in a collision to reduce the vehicle speed in the subsequent collisions. The effectiveness was estimated by an in-depth review of the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). The cases were extracted on the basis of the 3-point lap and shoulder belted occupants, incurring Maximum Abbreviated Injury Scale level 3 to 6 injuries (MAIS 3+), in the crashes occurred from 2004 to 2006, without vehicle rollover or occupant ejection, where the involved vehicles were 2000 and newer model year cars and light trucks.

A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries.

A logistic regression analysis of accident cases in the NASS-PCDS (National Automotive Sampling System-Pedestrian Crash Data Study) database clearly shows that pedestrian pelvis injuries tend to be complex and depend on various factors such as the impact speed, the ratio of the pedestrian height to that of the bonnet leading edge (BLE) of the striking vehicle, and the gender and age of the pedestrian. Adult female models (50th %ile female AF50: 161 cm and 61 kg; 5th %ile female AF05: 154 cm and 50 kg) were developed by morphing the JAMA 50th %ile male AM50 and substituting the pelvis of the GHBMC AM50 model. The fine-meshed pelvis model thus obtained is capable of predicting pelvis fractures. Simulations conducted with these models indicate that the characteristics of pelvis injury patterns in male and female pedestrians are influenced by the hip/BLE height ratio and to some extent by the pelvis bone shape.

The Flexible Pedestrian Legform Impactor (Flex-PLI) was developed to evaluate the risk of pedestrian lower extremity injuries. However, it has been pointed out that the post-crash kinematics of the Flex-PLI differs from those of a human body when it is hit by high-bumper vehicles. This paper describes the feasibility of applying the Flex-PLI to a wide range of vehicle types by adding a supplemental weight. The following aspects are discussed in this regard: A human body finite element (FE) model analysis shows that the upper body of the Flex-PLI is not involved in tibia and knee ligament injury indexes in the first contact with a high-bumper vehicle. A rigid bar model is introduced and its rotational energy ratio is formulated. The rotational energy ratio is employed to evaluate the post-crash kinematics of the Flex-PLI and a human leg model. The feasibility of adding a supplemental weight to the Flex-PLI with regard to the bumper height is discussed.

Implementation of appropriate safety measures, either from the viewpoint of a vehicle or the society or the infra-structure, it is an important issue to clearly understand the multi-dimension complicated real world accident scenarios. This study proposes a new method to easily capture and to extract the essence of such complicated multi-dimension mutual relationship by visualizing the results of SOM (Self Organizing Map). The FARS data from 2010 is used to generate a dataset comprised of 16,180 fatal passenger car drivers and 48 variables. The 16,180 fatal drivers were clustered using hierarchy cluster analysis method and mapped into a two-dimensional square with one dot representing one fatal driver using SOM.

This paper presents a method for optimizing occupant restraint system parameters in vehicle frontal crashes. Simulation models incorporating restraint systems and dummies are used for predicting injury indexes. A full-scale survey of all of the design parameters related to the injury indexes would require a vast number of simulations. Therefore, the Design of Experiments (DOE) method involving a minimum number of experiments is more realistic. However, dummy behavior often shows discontinuity if the dummy comes in contact with the steering wheel, so it is not predicted well with usual DOE methods. This paper shows how to incorporate such discontinuity in a DOE study and how to optimize the restraint system parameters to reduce occupant injury indexes. It also discusses the feasibility of this method for integrated optimization of 50th percentile and 5th percentile dummies.

Analyses were performed using field data for belted drivers of light vehicles in frontal crashes to examine the frequency and severity of frontal crashes with narrow objects. This study examined the distribution of injuries by body region, crash severity, and single- versus multiple-vehicle crashes for narrow object and all other crashes. Factors influencing injuries in different types of frontal crashes were identified, and risk of injury to belted drivers in narrow object crashes versus other frontal crashes was examined. A detailed review of about 400 NASS cases involving narrow object crashes was also performed. Results indicate frontal crashes involving impact with poles, posts, or trees are relatively infrequent. Overall, the fatal risk for belted drivers is lower in narrow object crashes than in other types of frontal crashes.

Vehicle impact compatibility is recognized as an approach to further enhance vehicle safety performance. In front-to-front impacts, through many studies in the world, the fundamental issues of compatibility have become more clear. Meanwhile, in front-to-side impacts, especially front of SUV to side of car impacts, fundamental research on compatibility is not as advanced. Considering the above, front of SUV to side of car impact tests were conducted and the issues of compatibility in front-to-side impacts were analyzed.

The numerical relations between occupant restraint systems and injury indexes were investigated by multi-parameter optimization of an integrated restraint system model of frontal crash simulations. This paper proposes a method of optimizing restraint systems in two types of test configurations: a 35-mph full overlap crash model and a 40-mph 40%-offset crash model.