Vehicles speed analysis in roundabouts vicinity

Driving speed is one of the most important factors in road safety as it not only affects the severity of a crash but it is also related to the risk of being involved in a crash. One of the solutions for improving safety in cities is to design new and replace already existing crossroads by roundabouts which offer improved safety over other types of intersections having fewer conflict points, slower speeds and easier decision making. Previously conducted studies considering traffic safety at crossroads in Bialystok have confirmed lower number of accidents and casualties at roundabouts when compared to other types of junctions but at the same time the number of collisions remained at unexpectedly high level. The paper presents the survey of instantaneous speed, decelerations and accelerations in vicinity of chosen roundabouts located in Bialystok. The data was gathered by utilizing a portable wireless GPS data logger that allowed monitoring and recording second-by-second in-field vehicle position along the tested sections.