Predictable road user behaviour by a recognizable road design: a theoretical and practical exploration

'Predictability' is an important principle for achieving a sustainably safe road traffic. This means that the road design must be so recognizable for the road user that he can know what to expect on different roads, and how he is expected to behave at any given moment. The result should be a more uniform, and therefore more predictable, behaviour. This report is an exploratory study in preparation of further studies of recognizable road design and its influence on the predictability of road user behaviour. The report consists of an exploration of the theory behind terms such as 'recognizability' and 'predictability' and their mutual relation, as well as an exploration of the practical situation: What is being done nowadays to improve the recognizability of roads, and what knowledge is already available? The theoretical exploration was carried out with the help of mainly cognitive-psychological literature. An inventory was carried out of the practical situation among various road authorities who at this moment are occupied with making road types more recognizable. Recognizability is based on the fact that people categorize their observations. This categorizing takes place at different levels of detail, it is flexible, and dependent on context. The report is available at: http://www.swov.nl/rapport/R-2005-17.pdf