Performance Analysis of Modern Roundabouts as an Alternative to Conventional Signalized Intersections: a Comprehensive Review

摘要

The intersection is one of the most important elements of roadway network. It is considered as a point of weakness in any roadway network, because it has a higher probability of accident occurrences and a lower capacity than other elements of roadway network. During the last three decades, the roundabout has begun to be highlighted as a solution to problems of conventional signalized intersections. Since then, numerous studies have been conducted in order to determine and quantify the performance and benefits of converting the conventional signalized intersection to a modern roundabout. Most of these studies have focused on certain aspects of the performance of roundabouts, while neglecting the others. In addition, most of these studies have not determined the extent of conflicts among the different factors that affect the performance of the roundabout. This has necessitated the need for a comprehensive study that addresses all the aspects of roundabout performance and analyzes the interference among the different factors that affect the roundabout performance. In this study, the literature concerning all the aspects of a roundabout performance (safety of drivers, pedestrians, cyclists, as well as capacity, delay, toxic emissions, fuel consumption, cost) have been analyzed. In addition, the degree of interference among all the factors that affect the performance of a roundabout has been determined in order to clarify the overall picture of roundabout performance and finally to present the overall findings of the study.