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So far, analysis of real-world crashes has not made it possible to evaluate the occupant change of velocity in side impact. This change of velocity is the most pertinent of the lateral-collision violence parameters when occupants are exposed to intrusion by car bodies. The present paper describes a method for calculating this parameter, and includes a description of the data that must be collected concerning real-world crashes in order to enable its application. The validity of this method is demonstrated by its application to a series of experimental collisions. The results are highly correlated to the values resulting from the integration of the accelerations found for the pelvis and thorax. The method is then applied to 60 real-world car-to-car side collisions from the accident survey.

In 1344 car-to-car side collisions, the risk of serious or fatal injury to the occupants of struck vehicles seem to increase proportionally to the difference in mass ratios in favor of the striking vehicle. However, in-depth analysis of 63 collisions during which the impact occurred on the side panel of the passenger compartment reveals that the difference in mass ratios is not the principal determinant of injury severity. The frequency and severity of injuries correlates better with the amount of intrusion of the side panel, a type of intrusion which occurs almost systematically, and even at low impact speed, when the bumper and structure in front of the side rail of the striking car override the rocker panel of the struck car.

The 3-point static belts that are installed in Renault and Peugeot vehicles are equipped with a force limiter near the upper anchorage. This system is made up of several bands of textiles that tear successively for the increasing levels of force exerted by the occupant. One can thus associate, for each person in the accident, the degree of the thoracic AIS and the value of the support force, expressed in daN. This relationship is established for 92 belted occupants who were involved in frontal impacts. In addition it is indicated which are the distributions of impact violence parameters incurred and which are the distributions of ages in order to determine the statistical meaning of the required results. The levels of tolerance observed in this sample are compared to thoracic injuries observed on belted cadavers exposed to equivalent violent impacts.

One studies the conditions in which occurred side impacts having led to death of 369 car occupants. This sample is representative of the population of fatal collisions having occurred on French roads, in 1980. 28 % of killed were victims of collisions against another private car, 34 % struck a fixed obstacle, 21 % undergone a collision against a truck. The other types of collisions account for 17%. The performances to be reached in order to spare an important number of victims are of a high level. This is measured in function of the distribution of impact violences and occupants' ages.

This study aims at determining, with the maximum precision, the performance of the 3 point safety belt in different accident configurations, and more particularly in frontal collisions. For this purpose, two matched samples were taken from a file of 3000 accidents, analysed by a multidisciplinary study group. These samples of 100 front seat occupants wearing seat belts, and 100 not wearing seat belts were made up in such a manner that, for every belted occupant, corresponds an occupant not wearing a belt, the one and the other being in equivalent circumstances, using the following factors: Make and type of the vehicle Seat occupied Age (as far as possible) Direction of impact Violence of the impact (same class of ▵V and mean γ) Possible intrusion of passenger compartment Possible overload caused by a rear seat occupant Using this method of comparison, one can appreciate the effectiveness of the 3 point belt and explain the variations of effectiveness that appear in normal case studies.

THE FREQUENCY AND SEVERITY OF LESIONS SUSTAINED BY THE OCCUPANTS OF CARS IMPACTED LATERALLY depend upon the main following factors: impact localization, intrusion into passengers' compartment, car speed variation, direction of occupant trajectory, objects contacted by the various body areas. 296 lateral impacts are being described hereunder by means of factors below. Consequences are drawn therefrom as to the coming improvement of occupant protection taking account of the current state of the art in Biomechanics and automobile technique. IN COMPARISON WITH THE PROGRESS achieved with a view to improving occupant protection against frontal impact, the knowledge available on the lateral impact and the methods for reducing the severity thereof are very poor. In as much as the results achieved in biomechanics up to this date are known, there is still much to do in this field. Mc Elhaney (1)* already stressed the fact in 1971 after Snyder (2).

Several ambitious projects, such as the PROMETHEUS programme, have recently been promoted by groups of automobile manufacturers. These projects attest to the determination of vehicle designers to revolutionize the driver's environment in response to radical changes in road traffic systems. The success of these programs will largely depend on the manner in which the Driver-Vehicle-Environment interface is achieved. A key aspect will be to provide drivers with all the help they need, via intelligent electronics, to make their driving as safe as possible. Below will be discuss the main areas of ergonomics which require the greatest research efforts as well as areas in which our experience allows us to make an original contribution.