A Model of Human-Machine Interaction for Risk Analysis in Road Traffic : A Cognitive Systems Engineering Approach

The main purpose of the thesis is to discuss the accident models which underlie accident prevention in general and road safety in particular, and the consequences of relying on a particular model have for actual preventive work. The discussion centres on two main topics. The first topic is whether the underlying accident model, or paradigm, of traditional road safety should be exchanged for a more complex accident model, and if so, which model(s) are appropriate. From a discussion of current developments in modern road traffic, it is concluded that the traditional accident model of road safety needs replacing. An analysis of three general accident model types shows that the work of traditional road safety is based on a sequential accident model. Since research in industrial safety has shown that such model are unsuitable for complex systems, it needs to be replaced by a systemic model, which better handles the complex interactions and dependencies of modern road traffic. The second topic of the thesis is whether the focus of road safety should shift from accident investigation to accident prediction. Since the goal of accident prevention is to prevent accidents in the future, its focus should theoretically be on how accidents will happen rather than on how they did happen. Despite this, road safety traditionally puts much more emphasis on accident investigation than prediction, compared to areas such as nuclear power plant safety and chemical industry safety. It is shown that this bias towards the past is driven by the underlying sequential accident model. It is also shown that switching to a systemic accident model would create a more balanced perspective including both investigations of the past and predictions of the future, which is seen as necessary to deal with the road safety problems of the future. In the last chapter, more detailed effects of adopting a systemic perspective is discussed for four important areas of road safety, i.e. road system modelling, driver modelling, accident/incident investigations and road safety strategies. These descriptions contain condensed versions of work which has been done in the FICA and the AIDE projects, and which can be found in the attached papers.