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In order to reduce the number and severity of injuries to child occupants in car accidents, a great number of child restraint systems have been developed over the past years. Such systems must be adapted to the anthropometric characteristics of children and provide good protection; to achieve this, a knowledge of child tolerance to impact is required, but at present very little biomechanical data relating to children is available, especially for children in the first years of life. As the design, evaluation and certification of child restraint systems is performed with dummies and several dummy types are available- a relationship between dummy and expected child reactions must be identified. This paper, based on the work performed within the framework of the International Task Force on Child Restraint Systems*, proposes a comparison between child dummies and cadavers involved in identical experimental collisions, and restrained with child restraint systems.

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.

EUROSID is the side impact dummy that has been designed and has now been almost completely developed by a group of European research laboratories working together under the auspices of the European Experimental Vehicles Committee (EEVC). It represents a bringing together of components and ideas from the three experimental sided impact dummies sponsored by the EEC1 as part of their Biomechanics Programme. These were produced by APR (Peugeot-Renault), ONSER, and MIRA. This paper describes the evolution of the EUROSID dummy and discusses the advances in biofidelity, the responses of its various components to impact, and the types of measurements it can record.

No method based on experiments is convenient for evaluating globally the potential risk of a given vehicle for the whole population of pedestrians at risk, which encompasses the smallest children and the tallest adults simultaneously, when a large range of impact speeds has to be considered. Mathematical models are also inadequate, due to the large number of runs required for obtaining the probability of impact on each section of the front end profile. This paper describes first a recently improved mathematical method for defining the head trajectories yielded by experimental simulations or by a validated mathematical model. Then, a computer program is presented that simultaneously uses this method and statistical data concerning real accidents. The output of this program is a distribution of the impact probabilities for a given profile. The head impact velocities can be utilized for weighing the results. Possible improvements and application of this method are discussed.

PRAKIMOD has until now been mostly used for simulating pedestrian accidents. It is also a very convenient tool for studying frontal crashes, especially for determining the values of data that are not easily accessible from direct measurements. After a short description of the model and of the belt system, three examples of application are shown. The first one concerns the distribution of energy transfers from a dummy restrained by a shoulder belt and a knee bolster to the different parts of its environment and to the frontal structure of a car. The second one is an attempt to evaluate the respective influences of some parameters (such as the joint stiffnesses or mass distributions among the body parts) on the dummy's propensity for submarining. The third one concerns the problem of separating the effects of neck forces on the one hand, and of a direct impact on the steering wheel on the other hand.

Since July 1, 1973, the wearing of seat belts by front seat occupants is compulsory in France. This requirement is respected by 60 to 90% of motorists, depending on the type of road. If seat belts were not worn, a 55% increase in fatalities for front seat occupants would be observed. On the other hand, if seat belts were worn by occupants in all seats 100% of the time, fatalities would be reduced by another 30%. Improvements of the seat belt over the past ten years have had a significant influence in the following areas: - Incentives for wearing the belts - Limitation of belt stretch and spool-out - Reduction of the number of submarining cases. In this paper, emphasis is put on the levels of performance which no other sytem has been able to attain, or even equal, and which result in practically guaranteeing protection against the risk of ejection, especially in a side impact or rollover.

Safety of children as car occupants raises a specific problem: it is necessary to take into account two factors which are particular to them: their very fast growth and their behavior, which corresponds to a need for movement. An analysis of statistical and accidentological data, points to the fact that whereas traffic accidents account for 25 % of adult deaths, they account for nearly 50 % of deaths for children (all kinds of road-users). Measures were adopted in France; such as the obligation for children of less than 10-years-old to travel on rear seats of cars and the definition of an homologation procedure for children restraint devices, with the aim of limiting the consequences of these accidents. The most common restraint devices look like little individual seats and are designed to protect young children (less than 3-years-old). Recently, new restraint devices, called “cushions”, were developed.

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.

Car-pedestrian accidents were selected with reference to criteria like relevance in terms of injury severities representativity and reproducibility aiming to as accurate as possible reconstructions by dummy and cadaver tests. Parameters necessary for performance of these reconstructions were evaluated from the data of accident investigation teams. Preliminary tests were performed by research departments of automobile manufacturers to check the estimated conditions of these accidents before performing their reconstructions. A particular aim was to obtain insights into the mechanisms leading to injuries in pedestrian accidents; more generally reconstructing actual accidents is a privilegied approach to determine human tolerance limits and the corresponding protection criteria on dummies; the injuries resulting from the actual accidents are consequently compared with the data measured on dummies and cadavers in the reconstruction experiments.

A theoretical study was conducted to prove that the Part 572 dummy submarines more easily than human cadavers because of their different pelvic shapes. The three-dimensional geometrical definition of the lap-belt was developed in this paper for the study of the submarining problem. It was found that not only the lap-belt angles from side view (β1) but also from the upper view in respect to the X-axis (β2) play a significant role in the submarining tendency for each side. The anti-submarining scale is defined by a coefficient which is a function of both angles β1, β2 and the orientation of the upper half of the pelvic notch. A series of sled tests was performed on human cadavers, the Part 572 dummy and the modified dummy. Good agreement was found between the present theory and the experimental results.

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).

Collisions between vehicles and pedestrians are analyzed, in conjunction with a bidisciplinary “pedestrian” investigation, by simulating accidents using adult and child dummies. A series of experimental collisions were carried out at varying impact speeds with a sample of vehicles representative of the various front-end profiles of vehicles at present running on the roads, the purpose being to study how these profiles affect the kinematics of the adult and child and to define the risks of injury during the different phases of the accident. The degrees of severity of the impact against the vehicle and the ground are compared and head impact speeds analyzed. Countermeasures are proposed and an initial evaluation made using a cadaver.

Much progress has been made in many countries during recent years in detailed research into road accidents. The analysis facilities used by research workers to describe in a common language the severity of injuries and the deformation the vehicles undergo are improving. Assessment of the constraints to which the occupants of crashed vehicles are exposed is still too approximate, despite the fact that this is essential to interpret the progress achieved in the field of safety and to make decisions concerning the future. The methods used to analyze and classify accidents must reside on unquestionable physical basis. This is why Renault and Peugeot have discarded the Equivalent Test Speed method, replacing it by the Speed Variation method (ΔV) and, more recently, analysis based on two parameters, namely the speed variation and the mean deceleration of the undistorted part of the vehicle.