Roundabouts provide enhanced safety and lower operational costs compared to signalized intersections. However, the stochastic decision-making nature of human drivers (HVs) often leads to inefficient gap utilization, limiting roundabout efficiency. With the emergence of connected and autonomous vehicles (CAVs), these inefficiencies can be mitigated by leveraging CAVs as mobile traffic controllers. This research introduces a roundabout control framework designed to maximize mobility while ensuring equity between HVs and CAVs in a mixed-traffic environment. Operating optimally, CAVs work as mobile controllers, guiding HVs through the roundabout to minimize wait times. For this purpose, a two-dimensional spatiotemporal model is developed. To tackle the model’s complexity and implement it efficiently, the model is simplified to a single dimension using Frenet coordinates. A receding horizon technique is also utilized to address uncertainty and time complexity. In a case study, the proposed model is tested against a calibrated mixed traffic simulation under varying demand levels and CAV market shares. The results demonstrate significant improvements, with travel time reductions of 10% to 68%, delay reductions of 1% to 99%, and throughput improvements of 1% to 44%. Additionally, the methodology reduces delay variations for minor traffic compared to conventional mixed traffic simulations.
Mr. Abdullah Al Farabi is a transportation systems researcher specializing in developing advanced control algorithms to enhance urban mobility. His work integrates operations research techniques with traffic engineering to optimize traffic operation and mitigate congestion. Currently pursuing a Ph.D. in Civil and Transportation Systems Engineering at NC State University, he also holds an M.S. in Operations Research from the same institution. Farabi has contributed to urban congestion management by leveraging Vehicle-to-Everything (V2X) connectivity to design innovative traffic management solutions and autonomous vehicle control strategies. He has published and presented his findings at multiple prestigious conferences, including the Transportation Research Board (TRB) Annual Meeting and the INFORMS Annual Meeting.