A Speed Optimization Strategy for Smooth Merging of Connected and Automated Vehicles at T-Shape Roundabout

Abstract

This paper presents a novel holistic T-shape roundabout coordination system (TCS) that addresses the connected and automated vehicles (CAVs) flow in a typically isolated T-shape roundabout. The TCS optimizes the states of each approaching vehicle in a receding horizon control framework that aims to minimize the total crossing time, considering the vehicles' dynamic states. The control method ensures the comfortable crossing of each vehicle by retaining the basic features of a traditional traffic control management system. The optimal states are broadcasted ahead by TCS, which enables the CAVs to form a cluster and tune their speed in order to cross the roundabout with minimum stop-delay. We evaluate the effectiveness of the proposed TCS method under the various traffic flow demand. From the executed simulation, it is observed that the optimization process usually improves the average velocity, and reduces both the traffic density and vehicles' idling situation. As a consequence, the fuel consumption of each vehicle around the roundabout is also decreased. These outputs are compared with the traditional method, showing that the overall flow performance significantly improves in the case of the proposed scheme, and vehicles have rapid optimization for a smooth crossing.INDEX TERMS bi-level coordination, CAVs clustering, connected and automated vehicles, optimization, receding horizon control, T-roundabout,

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“…The results showed improved throughput and average speeds, as well as reduced total travel times. In turn, Jalil et al [33] conceptualized a novel holistic coordination system for CAVs at T-shaped roundabouts in order to optimize the traffic states of each approaching vehicle and to minimize the total delay time; the authors highlighted improvements in the average speed, traffic density, idling, and fuel consumption of vehicles around the roundabout where speed optimization ensured smooth crossing.…”