Abstract
A laboratory study has been made with a photographic material in order to investigate which criteria are used by drivers for decelerating at intersections. This study has been validated in the real situation. It gives data on the total influence of signals an on the effects of the different kinds of intersection signals. A factorial analysis has shown that six main factors were responsible of the driver's decision of deceleration when there is a signal. The more important of these factors are the visibility and the change of direction at the intersection of the road followed.