Stability of CACC-manual heterogeneous vehicular flow with partial CACC performance degrading

Abstract

ABSTRACTThe Cooperative Adaptive Cruise Control (CACC) system is beneficial to the traffic flow stability. However, the CACC mode will degrade to the ACC mode if a CACC vehicle following right behind a manual vehicle. This paper presents a framework for the analytical studies on the stability of the CACC-manual heterogeneous flow. ACC and CACC car-following models validated by the PATH program are used as surrogate models for degraded ACC vehicles and CACC vehicles respectively. The Intelligent Driver Model (IDM) is used as the manual driven car-following model. The stability of heterogeneous traffic flow is investigated theoretically under various CACC market penetration rates. It is found that the degradation of the CACC system leads to the deterioration of flow stability remarkably, which can be avoided by building a complete vehicle-to-vehicle communication environment. Parametric sensitivity analysis is conducted to give some suggestions for the enhancements of the stability of heterogeneous flow.