Contribution to evaluation of intermediate variables; background paper.

An important issue for evaluation is the discussion about the methodology of traffic safety research. There are two opposite approaches to traffic safety research, one starting from accident analysis, the other from the traffic process. In this background paper the stage is set for a discussion about the contribution of intermediate variables to evaluation, by making a plea for the second approach. The main argument regards the lack of theory in traffic safety research. There are a lot of notions about the causes of accidents but few of these notions are tested by means of scientific methods. It is argued that if the purpose of evaluation is primarily to learn from our activities in the past, then it is not enough to state results by means of the outcomes with regard to accidents, but also to investigate how these results are accomplished