An Analysis on Impact of Roundabout Geometric Elements on Driving Behavior

Abstract

For the safety performance and smooth operation of roundabouts, designing geometric elements that can realize appropriate driving behavior is an important issue, particularly regarding the S-shaped trajectory which is different from ordinary intersections. However in Japan, this kind of roundabout driving behavior characteristics has not yet been studied enough. In this study, video surveys for driving behavior by using an UAV were carried out at four roundabouts with different geometric design and their impacts on driving behavior are analyzed. As a result, the entry radius and the angle between entry and exit legs are shown as critical factors for the speed-curvature relationship concerning travelling stability as the characteristics of driving behavior. And also, in order to reduce the unfavorable variation in driving behavior, it is suggested that entry radius should not be overdesigned.