In 1995, a project was carried out by TRL to provide guidance to motor manufacturers about the types of equipment which are likely to be most effective in reducing the number of accidents. This was achieved by examining extensive samples of accidents to determine their causes. This paper describes the methods used to collect the accident data and the conclusions that were reached about the factors which cause car accidents. Two samples of over 1000 accidents were studied: one consisted of fatal accidents reported by the police and the other consisted of much less serious accidents reported by drivers to their insurer. A common system was developed for coding the causation factors in both sets of accidents. First, the Precipitating Factor or Factors in an accident were identified: these are the failures or manoeuvres that led directly to the accident. Then, the Causation Factor or Factors for each Precipitating Factor were identified: these are the causes for the failures or manoeuvres. Seven major clusters of accidents were identified from the combination of Precipitating and Causation Factors. Among fatal accidents these comprise pedestrian accidents and accidents involving loss of control because of excessive speed or a driver's lack of judgement of the car's path. The clusters of non-fatal accidents involve cars hitting other vehicles or objects in the carriageway because the driver was distracted, failed to judge the other vehicle's speed or was travelling too fast, also loss of control caused by ice or snow. (A)
Samenvatting