Abstract
No established body of knowledge exists which deals with the effects of priority rules and regulations on road user behaviour. Amongst the municipal authorities in the Netherlands two distinct attitudes are prevalent regarding the introduction of priority regulations at intersections in their jurisdiction. The evidence that can help decide what attitude is correct is scarce, and it stems exclusively from before and after studies. What is needed for the evaluation of priority rules and regulations is knowledge of what goes on in people's minds when they have an encounter that could develop into a conflict (or worse), and what behaviour they display as a consequence.