Effects of CAV on the stability and energy consumption of heterogeneous traffic flow system

Abstract

With the progression of intelligent and interconnected traffic system, a convergence of traffic stream is anticipated in the foreseeable future, where both connected automated vehicle (CAV) and human driven vehicle (HDV) will coexist. In order to examine the effect of CAV on the overall stability and energy consumption of such heterogeneous traffic system, we first take into account the interrelated perception of distance and speed by CAV to establish a macroscopic dynamic model utilizing the full velocity difference (FVD) model. Subsequently, drawing upon the linear stability theory, we propose the linear stability condition for the model using the small perturbation method，and the validity of the heterogeneous model is verified comparing with the FVD model. Through nonlinear theoretical analysis, we further derive the KdV-Burgers equation, which captures the propagation characteristics of traffic density waves. Finally, by means of numerical simulation experiments utilizing a macroscopic model of heterogeneous traffic flow, the effect of CAV permeability on the stability of density waves in heterogeneous traffic flow and the energy consumption of the traffic system is investigated. Subsequent analysis reveals emergent traffic phenomena. The experimental findings demonstrate that as CAV permeability increases, the ability to dampen the propagation of fluctuations in heterogeneous traffic flow gradually intensifies when giving system perturbation, leading to enhanced stability of the traffic system. Furthermore, higher initial traffic density renders the traffic system more susceptible to congestion, resulting in local clustering effect and stop-and-go traffic phenomenon. Remarkably, the total energy consumption of the heterogeneous traffic system exhibits a gradual decline with increasing CAV permeability. Further evidence has demonstrated the positive impact of CAV on heterogeneous traffic flow. This research contributes to providing theoretical guidance for future CAV applications, aiming to enhance urban road traffic efficiency and alleviate congestion.