COM-Roundabout: The first smart commutable and self-regulating roundabout for HDVs and CAVs

In the last decades, many new types of roundabouts and traffic regulation systems have been introduced in several countries. However, some issues related to their performance and safety remain. This article presents a new concept of self-regulating smart roundabout recently ideated: the COM-Roundabout (Commutable Roundabout), where the number of active entry and circulating lanes is dynamically adjusted in real time depending on the measured traffic demand intensity. The COM-Roundabout utilizes vehicle and queue detectors, smart cameras, LED road markers, and Variable Message Signs (VMS) to guide traffic into appropriate lanes dynamically. Performance in terms of capacity, delay, level of service and predicted accident rates is evaluated in many traffic scenarios, based on an extensive dataset of one million Origin-Destination traffic matrices (M O/D ), considering both Human-Driven Vehicles (HDVs) and Cooperative Autonomous Vehicles (CAVs), applying robust and widely used estimation methods (HCM and HSM models). This research demonstrates that the COM-Roundabout could be used to optimise real-time performance (e.g. capacity and LOS) and safety thanks to the numerous layouts and traffic control programmes adaptable to specific traffic conditions.