The utmost goal, where this work can be seen as a starting point, is to provide a framework for a more thorough description and analysis of safety related road user behaviour in order to better understand the different parts forming the traffic safety processes. The background is that it is problematic to use accident data analysis in the everyday traffic safety work due to low occurrence rates (for statistical purposes), lack of information about the behavioural aspects, varying degree of reporting, etc. Even serious conflicts, as they are defined in the Swedish Traffic Conflicts Technique, share some of the shortcomings that the accidents face like i.e. that the primary focus is set on rather exceptional and unsuccessful events. A future and expanded framework for describing the relation between traffic behaviour and safety must consider the following aspects: the importance of feedback to the road users; inclusion of more frequent events linked to a severity dimension; and prediction of safety/risk based on the more frequent events. By constructing severity hierarchies based on a uniform severity dimension (time-to-accident/speed value) it is possible to both describe the closeness to an accident and to get a comprehensive understanding of the connection between behaviour and safety by both considering unsuccessful and successful interactive situations. These severity hierarchies would make it possible to consider road users' expectations due to feedback and estimate its safety relevance. They would also increase the prospect of making reliable predictions about safe/unsafe environments. For the covering abstract see ITRD E124693.
Abstract