How to Make Roundabout Operations Manageable in a Connected Mobility Environment?

Abstract: Roundabouts have increasingly garnered attention from transportation authorities at various levels as a cost-effective solution for mitigating traffic crossing issues. However, unregulated or unmanaged flow of vehicles entering the roundabout can lead to inefficiencies in its operation. These arrivals occur when there is no active coordination or control over the timing and volume of vehicles approaching the roundabout from different directions. Such an “unattended traffic arrivals problem” is often a significant factor affecting the performance and intended advantages of traditional modern roundabouts. With the growing presence of connected vehicles on the road, it is crucial to explore the potential of leveraging Connected and Automated Vehicle (CAV) technologies to address these issues. This paper presents a methodology to 1) identify the characteristics of the unattended traffic arrivals based on literature review; and 2) explore the potentials of using advanced technologies like CAV and intelligent signal control system to coordinate and regulate the flow of traffic approaching the roundabout, thereby improving efficiency and safety. To that end, the underlying mechanisms of using CAV-enabled data analytics are proposed to depict the concept of operations for an envisioned managed roundabout traffic control system. In addition to mitigating the impact of unbalanced traffic flows from upstream intersections, the managed roundabout system also aims at preventing potential spillbacks from downstream intersections through coordinated signal control at both upstream and downstream locations. Primary simulation results are adapted in support of the proposed methodological concepts. Notably, this study offers a solid foundation for future research, including the design of on-site experimental studies.