This rating system is intended to provide a systematic and logical assessment of the secondary safety design of cars. At this stage, the rating system is concerned only with the car occupants and does not consider how the design of the exterior of the car may affect pedestrians and other unprotected road users. Because a large proportion of unprotected road users are injured by striking the outside of cars, this area of design is in practice very important and should not be ignored. However, the study of pedestrian accidents and the understanding of how vehicle design affects the pedestrian's injuries has only been the subject of major research efforts for the past ten years or so. The state of knowledge at present is sufficient to make some attempts to assess pedestrian safety design, but this will probably be more difficult than interior design, at least initially. In the authors' view, this is an area which should be explored in the near future perhaps with the intention of developing a separate 'pedestrian' safety rating. It will almost certainly be better to keep this distinct from the 'occupant' safety rating system described in this document. In developing this rating system, data from accident studies has been used wherever possible to provide objective guidance as to the relative importance of particular features and designs. There are inevitably areas where suitable data does not exist, at least publicly, and subjective estimates have had to be made in these areas. In most cases, it would in principle be possible to extract useful data from existing databanks if access could be arranged. These databanks could also be used as a further check on the reliability of data that is available. Items where acquisition of further data is felt particularly important are noted in the text. The use of accident data covering the whole vehicle population provides data on the 'average' performance of current vehicle design. In some areas, poor design could potentially have a relatively catastrophic effect for an individual model of car and its occupants. This will have only a small effect on the 'average' current design. For the critical items where bad design may have particularly severe consequences, special treatment of the value weights within each variable will be adopted. The first section of this report describes the development of the 'variable' weights, i.e. covers how the weights describing the relative importance of the 57 variables assessed in the car inspection were devised. The second section of the report deals with the 'value' weights, that is the importance of the different categories within each variable. (Author/publisher)
Abstract