Abstract
The purpose of this study was to prove three hypotheses: 1) visibility influences the speed of drivers in approaching an intersection; 2) the driver reduces his speed when he perceives other traffic and 3) priority is only respected when it corresponds with other characteristics of intersection. Particularly has been studied the conflict between priority and visibility. Three T-junctions were studied which were characterized by three types of visibility (good, limited, nil) and three types of priority (driver has priority, he has no priority, depends on driver's decision). Other characteristics: through traffic or no through traffic and perception of other traffic.