Evaluating Traffic Flow Effects of Cooperative Adaptive Cruise Control based on Enhanced Microscopic Simulation

Traffic flow effects of cooperative adaptive cruise control (CACC) have not been fully understood, though such understanding is essential for the forthcoming research and applications concerning connected and automated vehicles as well as the implication for future traffic management and control. This paper aims to explore the impacts of CACC on traffic flow efficiency based on in-depth microscopic simulation studies using an enhanced version of AIMSUN. First, the Gipps car-following and lane-changing models used by default in AIMSUN were replaced or enhanced with more advanced car-following and lane-changing models to improve the capability of the simulation system in realistically reproducing capacity drop phenomena and capturing traffic merging processes. Second, a simulation platform was established using the enhanced AIMSUN with respect to a 10-km Dutch freeway stretch that includes multiple bottlenecks involving recurrent congestion. Third, we explored on this simulation platform the impacts of CACC on traffic flow mixed with manually driven vehicles and CACC equipped vehicles, in consideration of a variety of CACC market penetration rates. The study results suggest that the CACC impacts are quite positive.