This work was performed to identify the few most important factors which control the incidence of traffic crashes and to categorise these factors in order of importance within a tentative framework aimed at clarifying approaches to crash reduction. Based on examining traffic accident data, traffic safety literature, and the discussion presented in the paper, a hierarchical framework is developed to organise what are judged to be the main factors controlling the incidence of traffic crashes. It is concluded that a number of factors are necessary to explain gross features observed in aggregate traffic crash data, and that approaches which attempt to explain such data in terms of just one factor (driver risk taking has been a popular choice of some recent attempts) are, at best, gross oversimplifications.
Abstract