Enhancing stability of traffic flow mixed with connected automated vehicles via enabling partial regular vehicles with vehicle-to-vehicle communication function

Stability analysis of mixed traffic flow consisting of both connected automated vehicles (CAVs) and regular vehicles (RVs) remains a challenging problem, particularly during the early stage of CAV penetration rates due to stability deterioration caused by the absence of vehicle-to-vehicle (V2V) communication function for CAVs following RVs without this V2V function. This paper presents an analytical approach to stability analysis of the mixed CAV-RV traffic flow by enabling partial RVs with V2V communications to provide connectivity function for CAVs upstream. The proposed analytical approach can be applied to regulate upgrade of RVs equipped with V2V function to mitigate stability deterioration and achieve stable conditions. To begin with, we define this new mixed CAV-RV traffic flow by considering partial RVs with V2V function. We proceed to derive general stability criteria of the mixed traffic flow, based on which the regulated upgrade of RVs equipped with V2V function can be analytically calculated to enhance mixed flow stability at varying CAV penetration rates. Finally, we conduct a numerical experiment to validate the effectiveness of the proposed analytical approach. As the result indicated, both CAV penetration rate and proportion of RVs with V2V function have significant impacts on stability of mixed traffic flow. The study underscores the importance of developing V2V communication connectivity features in a synchronized manner for both CAVs and RVs. By regulating the upgrade of RVs equipped with V2V function according to each CAV penetration rate, stability of the mixed traffic flow can be significantly enhanced.