The aim of the study was to clarify how knowledge elaborated by specific experience may lead to erroneous expectations during interactions between drivers and riders. Situation Awareness is partly determined by prior knowledge. Unshared knowledge may cause difficulties in managing driving interactions, but there is still an important gap in the literature devoted to this field of research. 226 participants were distinguished according to their use (type of vehicle driven, exclusive or dual drivers; and for the riders, the type of power two-wheeler used and its engine size) and their driving experience. Focusing on the most vulnerable users, prior representations to interactions were studied using a series of closed questions on drivers' performances relating to different stages of the interaction process from both the perspective of drivers' self-reflection and of riders' expectation. While most drivers are self-confident, their abilities tend to be questioned by riders. Owners of medium or large motorbike feel that drivers do not assess their approach speed accurately. Similarly, scooter riders doubt their ability to assess the distance that separates them from PTWs. Riders who use medium or large motorbikes are more likely to question drivers' skills in relation to crossing situations. Scooter riders do so more often for overtaking situations. The development of shared prior knowledge is essential to prevent accidents and incidents between drivers and riders. To help improve effectiveness, we recommend specific ways of embedding each type of road user profile in training, prevention and research.
