Connected and Automated Vehicles

Unsupervised Anomaly Detection in Multi-Agent Trajectory Prediction via Transformer-Based Models

Lyu, Qing
Fu, Zhe
Alexandre Bayen
2026

Identifying safety-critical scenarios is essential for autonomous driving, but the rarity of such events makes supervised labeling impractical. Traditional rule-based metrics like Time-to-Collision are too simplistic to capture complex interaction risks, and existing methods lack a systematic way to verify whether statistical anomalies truly reflect physical danger. To address this gap, we propose an unsupervised anomaly detection framework based on a multi-agent Transformer that models normal driving and measures deviations through prediction residuals. A dual evaluation scheme has been...

Position and Speed Estimation Using Deep Learning-Based KKL Observer in Mixed Autonomy Traffic Systems

Marani, Yasmine
Fu, Zhe
N'doye, Ibrahima
Feron, Eric
Laleg-Kirati, Taous-Meriem
Alexandre Bayen
2025

This paper proposes a deep learning-based Kazantzis–Kravaris–Luenberger (KKL) observer design to estimate position and speed in mixed-autonomy traffic environments. The approach relies on position measurements of vehicles surrounding the autonomous vehicle (AV), obtained through remote sensing, resulting in a subsequent time delay due to communication latency. The proposed deep learning KKL observer is designed to compensate for this delay and to ensure global asymptotic convergence of the estimation of position and speed by using a chain of sub-observers. We employ an unsupervised...

Lagrangian Control of Conservation Laws and Mixed Models

Alexandre Bayen
Maria Laura Delle Monache
Garavello, Mauro
Goatin, Paola
Piccoli, Benedetto
2022

A vehicle with different (eventually controlled) dynamics from general traffic along a street may reduce the road capacity, thus generating a moving bottleneck, and can be used to act on the traffic flow. The interaction between the controlled vehicle and the surrounding traffic, and the consequent flow reduction at the bottleneck position, can be described either by a conservation law with space dependent flux function [200], or by a strongly coupled PDE-ODE system proposed in [112, 208].

Centralized Traffic Control via Small Fleets of Connected and Automated Vehicles

Daini, Chiara
Goatin, Paola
Maria Laura Delle Monache
2022

In this paper we propose a model for mixed traffic composed of few Connected and Automated Vehicles (CAVs) in the bulk flow. We rely on a multi-scale approach, coupling a Partial Differential Equation describing the overall traffic flow and Ordinary Differential Equations accounting for CAV trajectories, which act as moving bottlenecks on the surrounding flux. In our framework, CAVs are allowed to overtake (if on different lanes) or merge (if on the same lane). Controlling CAV desired speeds allows to act on the system to minimize any traffic density dependent cost function. More precisely...

Cooperative Driving for Speed Harmonization in Mixed-Traffic Environments

Fu, Zhe
Kreidieh, Abdul Rahman
Wang, Han
Lee, Jonathan W.
Maria Laura Delle Monache
Alexandre Bayen
2023

Autonomous driving systems present promising methods for congestion mitigation in mixed autonomy traffic control settings. In particular, when coupled with even modest traffic state estimates, such systems can plan and coordinate the behaviors of automated vehicles (AVs) in response to observed downstream events, thereby inhibiting the continued propagation of congestion. In this paper, we present a two-layer control strategy in which the upper layer proposes the desired speeds that predictively react to the downstream state of traffic, and the lower layer maintains safe and reasonable...

Traffic Smoothing Using Explicit Local Controllers

Hayat, Amaury
Alanqary, Arwa
Bhadani, Rahul
Denaro, Christopher
Weightman, Ryan J.
Xiang, Shengquan
Lee, Jonathan W.
Bunting, Matthew
Gollakota, Anish
Nice, Matthew W.
Gloudemans, Derek
Zachár, Gergely
Davis, Jon F.
Maria Laura Delle Monache
Seibold, Benjamin
Alexandre Bayen
Sprinkle, Jonathan
Work, Daniel B.
Piccoli, Benedetto
2023

The dissipation of stop-and-go waves attracted recent attention as a traffic management problem, which can be efficiently addressed by automated driving. As part of the 100 automated vehicles experiment named MegaVanderTest, feedback controls were used to induce strong dissipation via velocity smoothing. More precisely, a single vehicle driving differently in one of the four lanes of I-24 in the Nashville area was able to regularize the velocity profile by reducing oscillations in time and velocity differences among vehicles. Quantitative measures of this effect were possible due to the...

Reinforcement Learning Based Oscillation Dampening: Scaling up Single-Agent RL algorithms to a 100 AV highway field operational test

Jang, Kathy
Lichtle, Nathan
Vinitsky, Eugene
Shah, Adit
Bunting, Matthew
Nice, Matthew
Piccoli, Benedetto
Seibold, Benjamin
Work, Dan
Maria Laura Delle Monache
Sprinkle, Jonathan M.
Lee, Jonathan
Alexandre Bayen
2024

In this article, we explore the technical details of the reinforcement learning (RL) algorithms that were deployed in the largest field test of automated vehicles designed to smooth traffic flow in history as of 2023, uncovering the challenges and breakthroughs that come with developing RL controllers for automated vehicles. We delve into the fundamental concepts behind RL algorithms and their application in the context of self-driving cars, discussing the developmental process from simulation to deployment in detail, from designing simulators to reward function shaping. We present the...

On the Analytical Properties of a Nonlinear Microscopic Dynamical Model for Connected and Automated Vehicles

Matin, Hossein Nick Zinat
Yeo, Yuneil
Gong, Xiaoqian
Maria Laura Delle Monache
2024

In this letter, we propose an integrated dynamical model of Connected and Automated Vehicles (CAVs) which incorporates CAV technologies and a microscopic car-following model to improve safety, efficiency, and convenience. We rigorously investigate the analytical properties such as well-posedness, maximum principle, perturbation, and stability of the proposed model in some proper functional spaces. Furthermore, we prove that the model is collision-free and derive an explicit lower bound on the distance as a safety measure.

Reinforcement Learning-Based Oscillation Dampening: Scaling Up Single-Agent Reinforcement Learning Algorithms to a 100-Autonomous-Vehicle Highway Field Operational Test

Jang, Kathy
Lichtle, Nathan
Vinitsky, Eugene
Shah, Adit
Bunting, Matthew
Nice, Matthew
Piccoli, Benedetto
Seibold, Benjamin
Work, Daniel B.
Maria Laura Delle Monache
Sprinkle, Jonathan
Lee, Jonathan W.
Alexandre Bayen
2025

In this article, we explore the technical details of the reinforcement learning (RL) algorithms that were deployed in the largest field test of automated vehicles designed to smooth traffic flow in history as of 2023, uncovering the challenges and breakthroughs that come with developing RL controllers for automated vehicles. We delve into the fundamental concepts behind RL algorithms and their application in the context of self-driving cars, discussing the developmental process from simulation to deployment in detail, from designing simulators to reward function shaping. We present the...

Traffic Control via Connected and Automated Vehicles (CAVs): An Open-Road Field Experiment with 100 CAVs

Lee, Jonathan W.
Wang, Han
Jang, Kathy
Lichtle, Nathan
Hayat, Amaury
Bunting, Matthew
Alanqary, Arwa
Barbour, William
Fu, Zhe
Gong, Xiaoqian
Gunter, George
Hornstein, Sharon
Kreidieh, Abdul Rahman
Nice, Matthew W.
Richardson, William A.
Shah, Adit
Vinitsky, Eugene
Wu, Fangyu
Xiang, Shengquan
Almatrudi, Sulaiman
Althukair, Fahd
Bhadani, Rahul
Carpio, Joy
Chekroun, Raphael
Cheng, Eric
Chiri, Maria Teresa
Chou, Fang-Chieh
Delorenzo, Ryan
Gibson, Marsalis
Gloudemans, Derek
Gollakota, Anish
Ji, Junyi
Keimer, Alexander
Khoudari, Nour
Mahmood, Malaika
Mahmood, Mikail
Matin, Hossein Nick Zinat
McQuade, Sean
Ramadan, Rabie
Urieli, Daniel
Wang, Xia
Wang, Yanbing
Xu, Rita
Yao, Mengsha
You, Yiling
Zachár, Gergely
Zhao, Yibo
Ameli, Mostafa
Baig, Mirza Najamuddin
Bhaskaran, Sarah
Butts, Kenneth
Gowda, Manasi
Janssen, Caroline
Lee, John
Pedersen, Liam
Wagner, Riley
Zhang, Zimo
Zhou, Chang
Work, Daniel B.
Seibold, Benjamin
Sprinkle, Jonathan
Piccoli, Benedetto
Maria Laura Delle Monache
Alexandre Bayen
2025

The CIRCLES project aims to reduce instabilities in traffic flow, which are naturally occurring phenomena due to human driving behavior. Also called “phantom jams” or “stop-and-go waves,” these instabilities are a significant source of wasted energy. Toward this goal, the CIRCLES project designed a control system, referred to as the MegaController by the CIRCLES team, that could be deployed in real traffic. Our field experiment, the MegaVanderTest (MVT), leveraged a heterogeneous fleet of 100 longitudinally controlled vehicles as Lagrangian traffic actuators, each of which ran a controller...