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Far-side occupants are not addressed in current government regulations around the world even though they account for up to 40% of occupant HARM in side impact crashes. Consequently, there are very few crash tests with far-side dummies available to researchers. Sled tests are frequently used to replicate the dynamic conditions of a full-scale crash test in a controlled setting. However, in far-side crashes the complexity of the occupant kinematics is increased by the longer duration of the motion and by the increased rotation of the vehicle. The successful duplication of occupant motion in these crashes confirms that a sled test is an effective, cost-efficient means of testing and developing far-side occupant restraints or injury countermeasures.

The biomechanical injury assessment for an occupant in a planar vehicle-to-vehicle collision often requires a kinematic analysis of impact-related occupant motion. This analysis becomes more complex when the collision force is eccentric to the center of gravity on a struck vehicle because the vehicle kinematics include both translation and potentially significant yaw rotational rates. This study examines the significance of vehicle yaw on occupant kinematics in eccentric (off-center) planar collisions. The paper describes the calculation of the instantaneous center of rotation (ICR) in a yawing vehicle post-impact and explores how mapping this quantity may inform an occupant’s trajectory when using a free particle “occupant” analysis. The study initially analyzed the impact-related occupant motion for all the outboard seat positions in a minivan using several hypothetical examples of eccentric vehicle-to-vehicle crash configurations with varying PDOF, delta-V, and yaw rate.

NHTSA has recently been petitioned to address the protection of second-row children in rear crashes due front seatback performance. The protection of children is important. However, it is more complex than assessing front seat performance in rear impacts. Viano, Parenteau (2008 [1]) analyzed cases of serious-to-fatally injured (MAIS 3+F) children up to 7 years old in the second row in rear impacts involving 1990+ model year vehicles using 1997-2005 NASS-CDS. They observed that intrusion was an important factor pushing the child forward into the back of the front seat, B-pillar or other front structure. To help assess whether stiffening the front seats would be beneficial for second-row child safety, the 2008 study was updated using more recent data and model year vehicles. In the present study, 1997-2015 NASS-CDS data were analyzed for serious-to-fatally (MAIS 3+F) injured 0- to 7-year old children in the second row with 1994+ model year vehicles.

The emergence of Plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) as a viable means of transportation has been coincident with the development of lithium-ion battery technology and electronics that have enabled the storage and use of large amounts of energy that were previously only possible with internal combustion engines. However, the safety aspects of using these large energy storage battery packs are a significant challenge to address. For example an unintentional sudden release of energy, such as through a thermal runaway event, is a common concern. Developing thermal management systems for upset conditions in battery packs requires a clear understanding of the heat generation mechanisms and kinetics associated with the failures of Li-ion batteries.

As a result of the development of Event Data Recorders (EDR) and the recent FMVSS regulation 49 CFR 563, today’s automobiles provide a limited subset of electronic data measurements of a vehicle’s state before and during a crash. Prior to this data, the only information available about the vehicle movements before or during a collision had come from physical evidence (e.g. tire marks), witnesses, aftermarket camera systems on vehicles, and ground-based cameras that were monitoring vehicle traffic or used for security surveillance. Today’s vehicles equipped with Advanced Driver Assistance Systems (ADAS) have vehicle-based sensors that measure information about the environment around a vehicle including other vehicles, pedestrians, and fixed wayside objects.

This study assesses front seat occupant responses in rear impacts with active head restraints (AHR) and conventional head restraints (CHR) using field accident data and test data from the Insurance Institute for Highway Safety (IIHS). 2003-2015 NASS-CDS data were analyzed to determine injury rates in 1997+ model year seats equipped with AHR and CHR. Results indicated that less than 4% of occupants were in seats equipped with AHR. Crashes of delta-V <24 km/h accounted for more than 70% of all exposed front seat occupants, irrespective of head restraint design. Rear crashes with a delta-V < 24 km/h included 35.6% fewer occupants who sustained a MAIS 1-2 injury overall and 26.4% fewer who sustained a MAIS 1-2 cervical injury in vehicles equipped with AHR compared to CHR. In IIHS 16 km/h rear sled tests, the biomechanical response of an instrumented BioRID was evaluated on seats with AHR and CHR. HIC15 and concussion risk were calculated from head acceleration data.

Obesity rates are increasing among the general population. This study investigates the effect of obesity on ejection and injury risk in rollover crashes through analysis of field accident data contained in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) database. The study involved front outboard occupants of age 15+ years in 1994+ model year vehicle rollover crashes. Occupants were sorted into two BMI groups, normal (18.5 kg/m2 ≤ BMI < 25.0 kg/m2) and obese (BMI ≥30 kg/m2). Complete and partial ejection risks were first assessed by seating location relative to roll direction and belt use. The risk of serious-to-fatal injuries (MAIS 3+F) in non-ejected occupants were then evaluated. The overall risk for complete ejection was 2.10% ± 0.43% when near-sided and 2.65% ± 0.63% when far-sided, with a similar risk for both the normal and obese BMI groups.

Vehicle structures are designed to manage impact forces and transfer crash energy, in addition to their primary purpose of connecting all the vehicle powertrain, suspension, steering, HVAC, electronics, occupant accommodation, and weatherproofing. With the introduction of new rear impact requirements, the design of rear structures has evolved and the use of high strength steel has increased. This study objective was to assess the effect of new FMVSS 301 requirements on vehicle responses. NHTSA conducted 33 offset rear crash tests at 80 km/h with vehicles that pre-dated the newer FMVSS 301R requirements and 88 with vehicles that complied with the newer requirements, with a 2009-2015 model year range. The vehicles were grouped by size and the permanent crush was tabulated. Overall, the struck-side maximum crush decreased in the newer model vehicles. Seven matches with pre and post 301R were identified on the same make and model vehicle of different generations.

This study assesses vehicle and occupant responses in six vehicle-to-vehicle high-speed rear impact crash tests conducted at the Exponent Test and Engineering Center. The struck vehicle delta Vs ranged from 32 to 76 km/h and the vehicle centerline offsets varied from 5.7 to 114 cm. Five of the six tests were conducted with Hybrid III ATDs (Anthropometric Test Device) with two tests using the 50th male belted in the driver seat, one test with an unbelted 50th male in the driver seat, one test with a 95th male belted in the driver seat, and one with the 5th female lap belted in the left rear seat. All tests included vehicle instrumentation and three tests included ATD instrumentation. The ATD responses were analyzed and compared to corresponding IARVs (injury assessment reference values). Ground-based and onboard vehicle videos were synchronized with the vehicle kinematic data and biomechanical responses.

A crash of a medium duty truck led to a study of the failure mechanism of the truck’s steering system. The truck, after being involved in a multi-vehicle vehicle collision, was found with its steering input shaft disconnected from the steering gear. The question arose whether the steering gear failure was a result of the collision, or causative to the collision. An in-depth investigation was conducted into whether forces on the vehicle due to the collision could cause the steering shaft to separate from the steering gear. Additionally, the performance of the steering gear with the adjuster nut progressively backed off was studied to determine the feedback a driver would receive if the steering gear came progressively apart. From the results of these studies, conclusions with regard to the crash causation were reached.

Extensive testing has been conducted to evaluate both the dynamic response of vehicle structures and occupant protection systems in rollover collisions though the use of Anthropomorphic Test Devices (ATDs). Rollover test methods that utilize a fixture to initiate the rollover event include the SAE2114 dolly, inverted drop tests, accelerating vehicle body buck on a decelerating sled, ramp-induced rollovers, and Controlled Rollover Impact System (CRIS) Tests. More recently, programmable steering controllers have been used with sedans, vans, pickup trucks, and SUVs to induce a rollover, primarily for studying the vehicle kinematics for accident reconstruction applications. The goal of this study was to create a prototypical rollover crash test for the study of vehicle dynamics and occupant injury risk where the rollover is initiated by a steering input over realistic terrain without the constraints of previously used test methods.

Many published studies have characterized walking and running speeds of young children. However, there is a paucity of data on the cycling speeds of very young children (4 to 5 years old). The purpose of this study was to obtain an estimate of cycling speed for boys and girls both who are learning to ride bicycles (i.e., younger children who still ride with training wheels) and who have already learned to ride bicycles (i.e., slightly older children who no longer use training wheels). A sample of 32 child riders (17 boys, 15 girls; 17 four-year-olds who still ride with training wheels, 15 five-year-olds who do not) were asked to ride a short pre-defined distance at their usual speed when riding, and again at their highest speed. We found that while age and experience can differentiate riders, there were only small differences between boys’ and girls’ speeds in either age group.

As the deployment of automated vehicles (AVs) on public roadways expands, there is growing interest in establishing metrics that can be used to evaluate vehicle operational safety. The set of Operational Safety Assessment (OSA) metrics, that include several safety envelope-type metrics, previously proposed by the Institute of Automated Mobility (IAM) are a step towards this goal. The safety envelope OSA metrics can be computed using kinematics derived from video data captured by infrastructure-based cameras and thus do not require on-board sensor data or vehicle-to-infrastructure (V2I) connectivity, though either of the latter data sources could enhance kinematic data accuracy. However, the calculation of some metrics includes certain vehicle-specific parameters that must be assumed or estimated if they are not known a priori or communicated directly by the vehicle.

Vehicle rear structure stiffness has increased as a result of the requirements in the FMVSS 301R, which has also corresponded to an increase in front-row seat strength. This study evaluates the structural behavior and occupant response associated with production-level seats equipped with body-mounted D-rings, and very stiff all-belt-to-seat (ABTS) in a group of 12 deceleration sled tests. A double-haversine pulse with approximately 100-msec duration was used for all tests, with peak accelerations of approximately 19 g for the 40 km/h (25 mph) tests and peak accelerations of 28 g for the 56 km/h (35 mph) test. This generic pulse was designed to represent a severe rear impact crash involving vehicles with stiffer rear structures. The tests compared occupant responses and resulting structural deformation of an original equipment manufacturer (OEM) production-level driver seat from a pickup and a very stiff modified ABTS. Both seating systems were equipped with dual recliners.

Occupant protection in rear crashes is complex. While seatbelts and head restraints are effective in rear impacts, seatbacks offer the primary restraint component to front-seat occupants in rear impacts. Seatback deflection due to occupant loading can occur in a previous rear crash and/or in multiple-rear event crashes. Seatback deflection will in-turn affect the plastic seatback deformation and energy absorption capabilities of the seat. This study was conducted to provide information on seatback deflection and seat energy consumption in low and high-speed rear impacts. The results can be used to examine seatback deflection and energy consumed in a previous rear impact, or in collisions with multiple rear impacts. Prior seatback deflection and energy absorption can affect the total remaining energy absorption and seat performance for a subsequent rear impact.

Assessment of the physical evidence on a seat belt restraint system provides one source of data for determining an occupant’s seat belt use or non-use during a motor vehicle crash. The evidence typically associated with loading from a restrained occupant has been extensively researched and documented in the literature. However, evidence of loading to the restraint system can also be generated by other means, including the interaction of an unrestrained occupant with a stowed restraint system. The present study evaluates physical evidence on multiple stowed restraint systems generated via interaction with unrestrained occupants during a full-scale dolly rollover crash test of a large multiple passenger van. Unbelted anthropomorphic test devices (ATDs) were positioned in the driver and right front passenger seats and in all designated seating positions in the third, fourth, and fifth rows.

In rear-end collisions, the seatback provides primary occupant restraint during initial rearward motion of the occupant relative to the vehicle interior as the vehicle is accelerated forward by collision forces. When properly used, seat belts contribute to limiting occupant excursion and loading by working in concert with the seatback, as well as managing forward excursion on rebound after rear-end impacts. A lack of data evaluating the role of seat belt restraint component technology in limiting occupant motion and loading during high-severity rear-end impacts has been identified. This knowledge gap is particularly apparent for occupants who are not seated normally, in position, at the time of impact. Previous static pretensioner deployment tests suggest that different combinations of latch plate design and pretensioner deployment strategies might have different effects on occupant restraint.

Crash reconstructions using finite element (FE) vehicle and human body models (HBMs) allow researchers to investigate injury mechanisms, predict injury risk, and evaluate the effectiveness of injury mitigation systems, ultimately leading to a reduced risk of fatal and severe injury in motor vehicle crashes (MVCs). To predict injuries, regional-level injury metrics were implemented into the Total Human Model for Safety (THUMS) full body HBM. THUMS was virtually instrumented with cross-sectional planes to measure forces and moments in the femurs, upper and lower tibias, ankles, pelvis (pubic symphysis, ilium, ischium, sacrum, ischial tuberosity, and inferior and superior pubic ramus), and the cervical, thoracic, and lumbar vertebrae and intervertebral discs. To measure accelerations, virtual accelerometers were implemented in the head, thoracic vertebrae, sternum, ribs, and pelvis. Three chest bands and an abdominal band were implemented to measure chest and abdominal deflection.

Through testing conducted by multiple facilities, it has been observed that the class of compact two-person vehicles designed exclusively for off-road operation known as Recreational Off-Highway Vehicles (ROVs) exhibit a range of steady-state handling characteristics - including both understeer and understeer transitioning to oversteer as measured in circle-turn tests similar to those set forth in SAEJ266. This handling characteristic is different from on-road passenger cars and light trucks which, under all but heavy loading conditions, exhibit linear range and limit understeer steady-state cornering behavior. Limit understeer is considered desirable for on-road vehicles because it provides a directionally stable and generally predictable control response. In the research presented in this paper, the handling qualities, including controllability, of a ROV which was modified to have different steady-state handling characteristics ranging from understeer to oversteer is examined.

This study was conducted to assess the effects of differing rear impact pulse characteristics on restraint performance, front-seat occupant kinematics, biomechanical responses, and seat yielding. Five rear sled tests were conducted at 40.2 km/h using a modern seat. The sled buck was representative of a generic sport utility vehicle. A 50th percentile Hybrid III ATD was used. The peak accelerations, acceleration profiles and durations were varied. Three of the pulses were selected based on published information and two were modeled to assess the effects of peak acceleration occurring early and later within the pulse duration using a front and rear biased trapezoidal characteristic shape. The seatback angle at maximum rearward deformation varied from 46 to 67 degrees. It was lowest in Pulse 1 which simulates an 80 km/h car-to-car rear impact.