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Motorized shoulder belt tensioning is a new automotive seatbelt technology which has shown promise to reduce automotive crash injuries. The current study was conducted to determine if the Hybrid III family of dummies is an appropriate biofidelic surrogate for studying motorized shoulder belt tensioning. The objective was to measure torso retraction time, torso position, torso velocity, internal resistive moment, changes in torso curvature and the center of rotation of torso extension during seatbelt tensioning for the Hybrid III family. A previous study developed a protocol and test fixture to measure the biomechanics of volunteers subject to quasi-static loading by a motorized shoulder belt tensioner. A fixture supported the occupant leaning forward and applied shoulder belt tension. Kinematics were quantified by analyzing the motion of reflective markers on the dummy using an eight camera digital video system. A three axis load cell measured internal resistance to extension.

Biomechanical surrogates are used in various forms to study head impact response in automotive applications and for assessing helmet performance. Surrogate headforms include those from the National Operating Committee on Standards for Athletic Equipment (NOCSAE) and the many variants of the Hybrid III. However, the response of these surrogates to loading at the chin and how that response may affect the loads transferred from the jaw to the rest of the head are unknown. To address part of that question, the current study compares the chin impact response performance of select human surrogates to that of the cadaver. A selection of Hybrid III and NOCSAE based surrogates with fixed and articulating jaws were tested under drop mass impact conditions that were used to describe post mortem human subject (PMHS) response to impacts at the chin (Craig et al., 2008). Results were compared to the PMHS response with cumulative variance technique (Rhule et al., 2002).

The National Highway Traffic Safety Administration (NHTSA) has recently opened a rulemaking docket seeking comments on the design of automobile seats and their performance in rear Impacts. There are two philosophies of seat design: one advocates rigid seats, the other advocates seats which yield in a controlled manner. A review of the legislative history of seat back design standards indicates that yielding seats have historically been considered a better approach for passenger cars. The design characteristics of current production automobile seats are evaluated and show no significant changes over the past three decades. Concerns about the performance of rigid seat backs in real world rear impacts are discussed, specifically increased injury exposure due to ramping, rebound and out-of-position occupants.

The purpose of this study was to investigate approaches evaluating the performance of safety systems in crash tests and by analytical simulations. The study was motivated by the need to consider the adequacy of injury criteria and tolerance levels in FMVSS 208 measuring safety performance of restraint systems and supplements. The study also focused on additional biomechanical criteria and performance measures which may augment FMVSS 208 criteria and alternative ways to evaluate dummy responses rather than by comparison to a tolerance level. Additional analysis was conducted of dummy responses from barrier crash and sled tests to gain further information on the performance of restraint systems. The analysis resulted in a new computer program which determined several motion and velocity criteria from measurements made in crash tests.

This paper summarizes work relating to the assessment of societal benefits of side impact protection. National Crash Severity Study (NCSS) and National Accident Sampling System (NASS) accident data technigues were reviewed with respect to the reliability of output information concerning the distribution of side impact accidents by impact severity and relationships between injury and impact severity. NCSS and NASS are confounded by errors and inadequacies, primarily as a result of improper accident reconstruction based upon the CRASH computer program. Based on review of several sample cases, it is believed that the NCSS/NASS files underestimate Lower severities and overestimate higher severities in side impact, with delta-V errors probably overestimated by 25-30 percent in the case of the more serious accidents. These errors cannot be properly quantified except on a case-by-case basis. They introduce unknown biases into NCSS/NASS.

Understanding of events within the history of a crash, and estimation of the severity of occupant interior collisions depend upon an accurate assessment of crash duration. Since this time duration is not measured independently in most crash test reports, it must usually be inferred from interpretations of acceleration data or from displacement data in high-speed film analysis. The significant physical effects related to the crash pulse are often essential in reconstruction analyses wherein the estimation of occupant interior “second collision” or airbag sensing issues are at issue. A simple relation is presented and examined which allows approximation of the approach phase and separation phase kinematics, including restitution and pulse width. Building upon previous work, this relation allows straightforward interpretation of test data from related publicly available test reports.

Purpose: A better understanding of rear occupant fatality risks is needed to guide the development of safety improvements for 2nd and 3rd row occupants. This study investigates fatal accidents of 1st, 2nd and 3rd row occupants by principal direction of force (PDOF), irrespective of restraint use. It determined the number of fatalities, exposure and fatality risk. Methods: 1996-2005 FARS was analyzed for occupant fatalities by seating position (1st, 2nd and 3rd row) and principal direction of force (1-12 o'clock PDOF, rollover and other/unknown). Light vehicles were included with model year 1990+. 1996-2005 NASS-CDS was similarly analyzed for occupant exposure. Fatality risk was defined as the number of fatalities in FARS for a given category divided by the exposure from NASS-CDS. Results: Ten percent (9.6%) of fatalities were to 2nd row occupants in FARS. About 2,080 deaths occur to 2nd row occupants annually. 38.4% died in rollovers and 26.8% in frontal crashes.

Child safety is an important issue. The objective of this study was to analyze field accident data for 0-7 year old children in the 2nd row by vehicle and crash type, irrespective of restraint use. The data was obtained from NASS-CDS for calendar years 1991-2005. Accidents were selected based on 2nd row occupancy in towaway light vehicles with model year 1990 or newer. Side impacts caused 30.9% of serious-to-fatal injury (MAIS 3+F) to 2nd row children followed by frontal impacts (29.8%), rollovers (24.4%) and rear crashes (15.0%). The highest risk for MAIS 3+F was in rollovers (2.8 ± 0.7%) followed by rear (1.4 ± 0.4%), side (1.0 ± 0.2%) and frontal (0.46 ± 0.10%) crashes. The differences are statistically significant (p <0.01). Individual rear and frontal impact cases were also reviewed to better understand injury mechanisms of children in the 2nd row. The cases were obtained from the 1997-2005 NASS-CDS electronic database.

The BSAN crash pulse model has been shown to provide useful information for restraint sensing evaluation and for structural force-displacement studies in flat fixed rigid barrier (FFRB) crashes. This paper demonstrates a procedure by which the model may be extended for use with central and offset vehicle to vehicle (VTV) crashes through appropriate combinations of vehicle parameters.

Objective: This study analyzes rear sled tests with a 95th% male and 5th% female Hybrid III dummy in various seating positions on ABTS (All Belt to Seat) seats in severe rear impact tests. Dummy interactions with the deforming seatback and upper body extension around the seat frame are considered. Methods: The 1st series involved an open sled fixture with a Sebring ABTS seat at 30 mph rear delta V. A 95th% Hybrid III dummy was placed in four different seating positions: 1) normal, 2) leaning inboard, 3) leaning forward and inboard, and 4) leaning forward and outboard. The 2nd series used a 5th% female Hybrid III dummy in a Grand Voyager body buck at 25 mph rear delta V. The dummy was leaned forward and inboard on a LeSabre ABTS or Voyager seat. The 3rd series used a 5th% female Hybrid III dummy in an Explorer body buck at 26 mph rear delta V. The dummy was leaned forward and inboard on a Sebring ABTS or Explorer seat.

Active head restraints are being used to reduce the risk of whiplash in rear crashes. However, their evaluation in laboratory tests can vary depending on the injury criteria and test dummy. The objective of this study was to conduct barrier tests with BioRID and sled tests with Hybrid III to determine the most meaningful responses related to whiplash risks in real-world crashes. This study involved: (1) twenty-four rear barrier tests of the Saab 9000, 900, 9-3 and 9-5 with two fully instrumented BioRID dummies placed in the front or rear seats and exposed to 24 and 48.3 km/h barrier impacts, and (2) twenty rear sled tests at 5-38 km/h delta V in three series with conventional, modified and SAHR seats using the Hybrid III dummy. A new target superposition method was used to track head displacement and rotation with respect to T1. Insurance data on whiplash claims was compared to the dummy responses.

Airbags and safety belts are now viewed as complements for occupant protection in a crash. There is also a view that no single solution exists to ensure safety and that a system of protective technologies is needed to maximize safety in the wide variety of real automotive crashes. This paper compares the fatality prevention effectiveness, and biomechanical principles of occupant restraint systems. It focuses on the effectiveness of various systems in preventing fatal injury assuming the restraint is available and used. While lap-shoulder belts provide the greatest safety, airbags protect both belted and unbelted occupants.

This paper covers the development of the General Motors Energy Absorbing Steering System beginning with the work of the early crash injury pioneers Hugh DeHaven and Colonel John P. Stapp through developments and introduction of the General Motors energy absorbing steering system in 1966. evaluations of crash performance of the system, and further improvement in protective function of the steering assembly. The contributions of GM Research Laboratories are highlighted, including its safety research program. Safety Car, Invertube, the biomechanic projects at Wayne State University, and the thoracic and abdominal tolerance studies that lead to the development of the Viscous Injury Criterion and self-aligning steering wheel.

This paper reviews issues relating to seats including design for comfort and restraint, mechanics of discomfort and irritability, older occupants, and low-back pain. It focuses on the interface between seating technology and occupant comfort, and involves a technical review of medical-engineering information. The dramatic increase in the number of features currently available on seats outreaches the technical understanding of occupant accommodation and ride comfort. Thus, the current understanding of seat design parameters may not adequately encompass occupant needs. The review has found many pathways between seating features and riding comfort, each of which requires more specific information on the biomechanics of discomfort by pressure distribution, body support, ride vibration, material breathability, and other factors. These inputs stimulate mechanisms of discomfort that need to be quantified in terms of mechanical requirements for seat design and function.

Objective: This study analyzed available rear impact sled tests with Starcraft-type seats that use a diagonal belt behind the seatback. The study focused on neck responses for out-of-position (OOP) and in-position seated dummies. Methods: Thirteen rear sled tests were identified with out-of-position and in-position 5 th , 50 th and 95 th Hybrid III dummies in up to 47.6 mph rear delta Vs involving Starcraft-type seats. The tests were conducted at Ford, Exponent and CSE. Seven KARCO rear sled tests were found with in-position 5 th and 50 th Hybrid III dummies in 21.1-29.5 mph rear delta Vs involving Starcraft-type seats. In all of the in-position and one of the out-of-position series, comparable tests were run with production seats. Biomechanical responses of the dummies and test videos were analyzed.

Objective: This study investigated the incidence of abdominal injuries in frontal crashes by occupant age and seating position. It determined the risk for abdominal injury (AIS 2+) by organ and injury source. Methods: 1997-2015 NASS-CDS was analyzed to estimate the occurrence of abdominal injuries in non-ejected, belted occupants involved in frontal crashes. Vehicles were included with 1997+ model year (MY). The annual incidence and rate for different types of abdominal injury were estimated with standard errors. The sources for abdominal injury were determined. Results: 77.8% of occupants were drivers, 16.7% were right-front passengers and 5.4% were rear passengers. Rear passengers accounted for 77.1% of 8-11 year old (yo) and 17.2% of 12-17 yo group. The risk for moderate abdominal injury (MAIS 2 + abdo) was 0.30% ± 0.053% in drivers, 0.32% ± 0.086% in right-front passengers and 0.38% ± 0.063% in rear occupants.

A case study was conducted of 123 crashes involving 144 fatally injured lap-shoulder belted front-seat occupants. The crashes occurred throughout the United States in 1985-86 and involved 97 driver and 47 right-front passenger deaths in new vehicles. A judgment was made by consensus of a safety panel on the potential for saving the victim's life by the addition of safety technology. Supplemental airbags provided the greatest potential for improving the life-saving effectiveness of current lap-shoulder belts. Overall, airbags may have prevented 12% of the belted occupant fatalities and 27% of the deaths in frontal crashes. The benefit of supplemental airbags was greater for the right-front passenger, in part, because of more females and occupants over 60 years of age in that seating position. A majority (68%) of the belted fatalities were judged unpreventable by reasonable restraint or vehicle modifications.

Field experience has consistently indicated that lap-only belts and lap-shoulder belts perform well and about equally in prevention of fatalities and serious injuries in the rear seating positions. Analyses based on overall usage and injury figures from the Fatal Analysis Reporting System (FARS), double-pair analysis of FARS data, and still older data bases have shown that, in the rear outboard seating positions, injury rates are about the same for lap-only and lap-shoulder belted crash occupants. Although sparse, recently available field data from the 1988-2001 National Analysis Sampling System / Crashworthiness Data System (NASS/CDS) files confirm the finding that, when used by rear seat occupants, lap-only belts perform about equally with lap-shoulder belts as countermeasures for serious and fatal injury in severe frontal crashes.

Child safety continues to be an important issue in automotive safety for many reasons, including reported cases of serious injury from airbag deployments. As a result of extensive public education campaigns, most children are now placed in rear seats of vehicles. Accordingly, a more precise understanding of rear-seat occupant protection is developing as the second and third rows have become the primary seating area for children in SUVs, vans and passenger cars. The objective of this study was to review field crash and injury data from rear seats, identify the distribution of children and infants in rear seats, and analyze injury risks in various crash modes. The database used was the 1991-1999 NASS-CDS. When looking at crash configurations for 1st and 2nd row children, rollover crashes involved the highest incidence of MAIS 3+ injury, followed by frontal and side impacts. Lap-shoulder belt usage was similar for 1st and 2nd row children.

Previous pendulum impact tests have shown that knee joint injuries and tibial-fibular fractures may occur when loads are directed against the lower leg rather than directly against the femur in the knee. In order to further improve our understanding of lower extremity restraint mechanics, simulated frontal barrier crash experiments were conducted with unembalmed human cadavers and an anthropomorphic dummy restrained by a two-point shoulder belt. In the first test, an experimental bolster was specifically positioned so that the cadaver's lower leg would strike the bolster, thus inducing restraining loads entirely below the knee joint. The analysis of occupant kinematics showed that the flexed knee rode over and forward of the low-positioned bolster. Restraint induced considerable shearing load across the knee joint. Bolster measurements indicated a peak load of approximately 4.0 kN per leg which resulted in a contralateral central tear of the posterior cruciate ligaments.