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A driver's preference for one of two different vehicle models that have the same measurable acceleration may be explained by complicated factors such as styling, NVH or ergonomics. If the vehicles have identical appearance but different levels of engine tune, discrimination would probably be due to the measurable difference in performance although other factors cannot be entirely discounted. If however, the assessment is made of vehicles with identical appearance and identical performance then any preference is attributable to an area of human assessment that has been termed subjective performance. This paper discusses the first step in a qualitative approach to the analysis of driver perception of vehicle performance and more specifically investigates subjective performance. The proposed model ascribes distinct components such as induced and perceived performance to the total subjective performance rating.

A large number of experiments involving cadavers - including real-world-accident reconstructions - have been performed for the purpose of enhancing the state of knowledge concerning tolerance levels and protection criteria relevant to side-impact conditions. However, the scatter of the findings, as well as the considerable differences in injury severity levels (differences that cannot be accounted for by age differences alone) have limited the conclusions that it was possible to draw from these investigations in terms of criteria, mainly concerning thoracic protection. The major cause of scatter is the considerable differences in skeleton quality between subjects. Analysis of the rib characterization test findings made it possible to define a thoracic resistance index enabling the establishment of a classification of subjects. This index, which was validated with our sample, allowed us to evaluate the pertinence of the various side-impact protection criteria considered.

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.

The data presented in this paper were yielded by tests performed on unembalmed human cadavers fitted with three-point seat belts and subjected to frontal collisions. The purpose is to define one or more functions predictive of thoracic injuries to cadavers whose rib “resistance” is known (i.e. BCF parameter (1)*). These functions predict the number of rib fractures and the thoracic AIS in terms of : anthropometrical data on the cadavers, data representative of the thoracic resistance of the cadavers and physical parameters arising from the deceleration pulses measured on the cadaver vertebrae during the occurrence of impact. By integrating the BCF data which characterize the ribs of the population exposed to the risk of thoracic injury, it is possible satisfactorily to define the tolerance of living road users, in terms of their age. Provided that maximum admissible injury level, and the age for which this limit is required are set, a tolerance criterion can then be defined.