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Nineteen sled impact tests were conducted simulating a frontal collision exposure for an unrestrained driver. The deceleration sled buck configuration utilized the passenger compartment of a late model compact passenger vehicle, a rigid driver's seat, and a custom fabricated energy-absorbing steering column and wheel assembly. Sled impact velocities ranged from 24.1 to 42.6 km/hr. The purpose of the study was to investigate the kinematic and kinetic interaction of the driver and the energy-absorbing steering assembly and their relationship to the thoracic/abdominal injuries produced. The similarities and differences between human cadaver and anthropomorphic dummy subjects were quantified.

The purpose of this paper is to present a comparison of whole body, target impingement knee impact response for a Part 572 dummy versus that for anthropometrically similar embalmed human cadavers. “Response” is defined here to include the impact force-time history as sensed by 1) femur load cells, and 2) impingement target load cells for the dummy and by the target load cells for the cadavers. The data presented demonstrate significantly higher peak forces and correspondingly shorter pulse durations for the dummy than for the companion cadaver subjects under similar test conditions and at all velocity levels investigated. For the dummy, the ratio of forces measured by the femur load cells to those measured by the impingement target load cells averaged eight tenths.

Previous studies of human thoracic injury tolerance and mechanical response to blunt, midsternal, anteroposterior impact loading were reported by the authors at the 1970 SAE International Automobile Safety Conference and at the Fifteenth Stapp Car Crash Conference. The present paper documents additional studies from this continuing research program and provides an expansion and refinement of the data base established by the earlier work. Twenty-three additional unembalmed cadavers were tested using basically the same equipment and procedures reported previously, but for which new combinations of impactor mass and velocity were used in addition to supplementing other data already presented. Specifically, the 43 lb/11 mph (19.5 kg/4.9m/s) and 51 lb/16 mph (23.1 kg/7.2 m/s) conditions were intercrossed and data obtained at 43 lb/16 mph (19.5 kg/7.2 m/s) and 51 lb/11 mph (23.1 kg/4.9 m/s).

At the 1970 SAE International Automobile Safety Conference, the first experimental chest impact results from a new, continuing biomechanics research program were presented and compared with earlier studies performed elsewhere by one of the authors using a different technique. In this paper, additional work from the current program is documented. The general objective remains unchanged: To provide improved quantification of injury tolerance and thoracic mechanical response (force-time, deflection-time, and force-deflection relationships) for blunt sternal impact to the human cadaver. Fourteen additional unembalmed specimens of both sexes (ranging in age from 19-81 years, in weight from 117-180 lb, and in stature from 5 ft 1-1/2 in to 6 ft) have been exposed to midsternal, blunt impacts using a horizontal, elastic-cord propelled striker mass. Impact velocities were higher than those of the previous work, ranging from 14-32 mph.

For the purpose of increasing available knowledge of human dynamic response and tolerance to thoracic impact, and experimental investigation of both blunt and localized impacts to embalmed and unembalmed human cadavers is being carried out. This is a progress report to date. Force and deflection time histories resulting from midsternal A-P impacts over a six inch diameter area and from blows localized near the costo-chrondral junctions were measured and cross plotted to provide dynamic force-deflection characteristics. The extent of skeletal damage was assessed by both radiological examination and thoracic dissection and is presented in relation to the impact parameters. X-ray assessment of rib fracture damage was found to be inadequate, revealing on the average less than half of the fractures confirmed by dissection.

Automobiles damaged in collisions in which the main vehicle structure has been underridden or overridden were studied, as well as injuries to occupants of the automobiles. The parameters that affect injuries are listed and discussed, as are the effects of these parameters for each case example. Recommendations are made for modifications of passenger cars, trucks, trailers, and highway furniture to mitigate the severity of injury in underride-override collisions.

Restraining devices continue to be the most effective means of lessening injuries in automobile collisions. Evidence from the Trauma Research Group's case files illustrates how injury is avoided or minimized by use of lap, shoulder, and diagonal seat belts in several types of crashes, under various angles of impact. Prevention of fatal ejection, the improved chances a restrained driver has of retaining control of his car, and the attenuation of interior collision forces, such as result in jackknifing, are topics discussed, as well as the contribution of major automobile design improvements.

A study was made of 290 collisions containing 464 front seat car occupants. Of the 405 injured occupants, 141 received their lower extremity injuries against the instrument panel. The occupant’s most serious injury was related to car model year, age of occupant, vehicle weight, and estimated impact speed. Statistically, a regression analysis shows a very strong correlation of these variables and collision injury. It is significant that the number of lower extremity injuries drops steeply for vehicles from 1957 through 1967. Rear seat occupant injuries were not considered in this paper.

Forces necessary for fracture under localized loading have been obtained experimentally for a number of regions of the head. Three of these, the frontal, temporoparietal, and zygomatic, have been studied in sufficient detail to establish that the tolerances are relatively independent of impulse duration, in contrast with the tolerance of the brain to closed-skull injury. Significantly lower average strength has been found for the female bone structure. Other regions reported upon more briefly are mandible, maxilla, and the laryngotracheal cartilages of the neck. Pressure distribution has been measured over the impact area, which has been 1 sq in. in these tests, and the relationship between applied force as measured and as predicted from a head accelerometer is examined.

Forty-six automobile collisions with 82 child occupants have been studied. Emphasis was placed on the mechanism of injury production and child collision kinematics. A number of case examples illustrate these injury patterns. Also included are example cases of the effects of collisions in pregnancy and cases of restrained children. Childhood growth characteristics as they affect injury patterns and restraint systems are discussed in detail. An analysis of current types of restraint systems is included and recommendations are made. Collision and comfort-convenience requirements of an “ideal” restraint system are listed.

Cardio-thoracic injuries comprise a significant segment of the injuries sustained in automobile collisions. Because of the urgent need for additional information which can lead to prevention of these injuries, The Vehicle Trauma Research group at the UCLA School of Medicine has instituted a medical-engineering study of these injuries. The study has attempted to correlate pathophysiologic aspects of the injuries with the kinematics and biomechanics of the collision. Particular attention has been paid to the effects of restraining devices and the relationship of injuries of various wheel-column configurations including “energy absorbing” designs. Sixty-seven cases have been completely analyzed to date and are presented as a preliminary pilot study illustrating the value of this type of approach to auto collision injuries.

A study was made of 54 collisions resulting in injuries to rear-seat occupants unrestrained by seatbelts. It was determined that children (who represent a disproportionate percentage of rear-seat occupants) tend to become airborne and to incur severe injuries against the windshield, miror, dashboard and header. Adults tend to injure the face and head against the front seat and to sustain typical leg fractures from trapping their feet under the front seat. The occupants seated at the outside edges of the rear seat sustain dangerous injuries from metal ashtrays and window crank handles out of proportion to the severity of the collision. All unrestrained rear-seat occupants add to the injuries of front-seat occupants by hurtling into them. Terminology to describe the types and severity of collisions is offered to facilitate medical and engineering evaluation of injuries. Recommendations are made for design changes to lessen hazards.

The Vehicular Trauma Research Group of the UCLA School of Medicine is currently conducting intensive studies of selected traffic accidents. Data is presented from an analysis of the first 150 traffic accidents studied. The role of vehicular design, mechanical failure and the performance of the new 1966 windshield in injury causation are discussed and illustrative examples are presented. The importance of detailed studies of traffic accidents is stressed as a method of yielding information not readily available by other methods of study. This approach is mandatory to evaluate new and pending vehicular design modifications and may be the only method of detecting and assessing the role of mechanical failure in traffic accident causation.

The research paper presented here is the result of an investigation by a medical-engineering team. The study applies techniques of experimental automobile-collision injury analysis to human injuries resulting from accidental collisions. The accident characteristics, observed injury patterns, and human kinematics are presented and analyzed. The study emphasizes injuries sustained from windshield glass. Present glass characteristics are discussed and suggestions based on the cases presented are made regarding future glass technology.