Traffic Flow on a Ring With a Single Autonomous Vehicle: An Interconnected Stability Perspective

Abstract

In recent years, field experiments have been performed on ring roadways with human-driven vehicles or with a mix of human-driven and autonomous vehicles. While these experiments demonstrate the potential for controlling traffic flows by a small number of autonomous vehicles, the theoretical framework about such a possibility is to a large extent incomplete. Indeed, most work on mixed traffic focused on classical asymptotical stability notions, neglecting that human drivers are prone to the interconnected instability known in the literature as string instability. This work aims to enhance the existing theories to meet the questions raised by the field experiments. It starts from the observation that the standard notion of string stability on a ring roadway is too demanding for a mixed traffic scenario: therefore, a new interconnected stability definition, named weak ring stability, is proposed. This new interconnected stability notion, in combination with classical stability, is able to explain phenomena observed in field experiments and to highlight possibilities and limitations of traffic control via sparse autonomous vehicle. Furthermore, it allows designing AV controllers with improved string stability specifications, at the price of reducing the sparsity of the autonomous vehicles.

Data-Driven Robust Predictive Control for Mixed Vehicle Platoons Using Noisy Measurement

“…Proof: It is easy to see that based on ( 16) and ( 20), Rt is governed by (21). Since [ A B] ∈ M AB as shown in Lemma 1, it is true that R t ⊂ Rt .…”

“…Hence, the OV model has been adopted for analyzing the stability of mixed platoon [18], [19] and developing model-based CACC for AVs within mixed platoons [17], [20]- [24]. Linear quadratic regulators are designed in [20], [21] for controlling an AV to smooth the mixed traffic flow on a ring road. Optimal control is developed in [17] for an AV to lead a number of HVs at a signalized intersection.…”

Connectivity and Automation as Enablers for Energy-Efficient Driving and Road Traffic Management

“…In mixed-traffic conditions, HVs have a strong influence on traffic flow as they increase the spread of shock waves in the downstream direction, causing stop-and-go waves (Di Vaio et al, 2019). As indicated by Giammarino et al (2020), CAVs can be designed to explicitly stabilize the traffic flow and actively dampen stop-and-go waves, which are particularly energy consuming. Vinitsky et al (2018) present such approaches based on reinforcement learning (RL) strategies.…”

An Adaptive Disturbance Decoupling Perspective to Longitudinal Platooning

“…Recent results include the introduction of delay-based spacing policy [8], the study of automated vehicles in a partial differential equation domain [9], the issues of safety [10] and cyber-security [11], [12], [13], dealing with heterogeneity in vehicle engine dynamics [14], [15], or with nonlinearity [16], [17]. Practical aspect related to vehicle state estimation have also been reported [18], [19], as well as reallife experiments [20], [21], [22].…”