Saad,, F., Institut National de Recherche sur les Transports et leur Scurit (INRETS), France
In the field of Traffic Psychology, many studies have been devoted to an analysis of drivers' errors, violations or risk taking, which are mainly based on accident investigation, outside observation of drivers' behaviour, laboratory experiments or surveys. Very few studies have examined in detail the context in which such deviations occur in normal driving situations, how and by whom (the driver himself or the other participants) the consequences of these deviations are recovered. The aim of this paper is to discuss the issues raised when analysing such drivers' deviations and identifying the psychological mechanisms and the factors likely to explain their occurrence. We will first examine the issue of norms or reference tasks in relation to which different classifications of driving deviations could be defined (deviations for the safety expert, for the drivers themselves, degree and severity of the observed deviations, ...). We will then discuss the contribution of an in-depth analysis of drivers' activity in real traffic situation, combining on-board observations of drivers' behaviour, and drivers' verbal report and interviews. The main results of two studies carried out on motorway will be presented which enables us to identify a number of critical driving situations, where drivers' deviations could be seen either as the cause or the consequence of these situations. As a conclusion, we will emphasise the contribution of such in-depth analysis for designing and assessing new driver support system.