Safety

A Zoox and an e-bike collided in S.F. Here’s what it says about robotaxi safety

May 13, 2025

San Francisco Chronicle Scott Moura, Faculty Director of Partners for Advanced Transportation Technology (PATH) and Professor of Civil and Environmental Engineering, alongside Matt Raifman SafeTREC researcher, and Steven Shadover PATH researcher discuss A Zoox and an e-...

Anatomy of a Crash

Marzuoli, Aude
Boidot, Emmanuel
Feron, Eric
Erp, Paul B. C. van
Ucko, Alexis
Bayen, Alexandre M.
2014

Transportation networks constitute a critical infrastructure enabling the transfers of passengers and goods, with a significant impact on the economy at different scales. Transportation modes, whether air, road or rail, are coupled and interdependent. The frequent occurrence of perturbations on one or several modes disrupts passengers' entire journeys, directly and through ripple effects. The present paper provides a case report of the Asiana Crash in San Francisco International Airport on July 6th 2013 and its repercussions on the multimodal transportation network. It studies the...

Mobile Phones and Social Media Empower the Citizen Seismologist

Bray, J.
Dashti, S.
Reilly, J.
Bayen, A.M.
Glaser, S.D.
2014

Emergency responders must "see" the effects of an earthquake clearly and rapidly for effective response. Mobile phone and information technology can be used to measure ground motion intensity parameters and relay that information to emergency responders. However, the phone sensor is an imperfect device and has a limited operational range. Thus, shake table tests were performed to evaluate their reliability as seismic monitoring instruments. Representative handheld devices, either rigidly connected to the table or free to move, measured shaking intensity parameters well. Bias in 5%-damped...

Future Road Transportation Technology

Wang, Junhua
Iwasaki, Randy
Bayen, Alexandre M.
Harvey, John
2016

As road transportation brings us great life changes, it also brings safety and environment problems. Near one million people died in road accidents each year and road constructions consumed un-countable ...

Continual Learning of Microscopic Traffic Models Using Neural Networks

Farid, Yashar Zeinali
Kreidieh, Abdul Rahman
Khalighi, Farnoush
Lobel, Hans
Bayen, Alexandre M.
2021

In a mixed-autonomy traffic scenario, where human drivers and autonomous vehicles share the streets, self-driving cars need to be able to predict in a robust manner the behaviour of human-driven vehicles, in order to guarantee a safe and smooth driving experience. Although traffic theory provides several models of human drivers, these models are often parameterized by few parameters which can limit their performance in modeling complex behaviors. The lack of sufficient model capacity and the behavioral shifts in human driving reduces the usefulness of these methods in real-life...

Reachability Analysis for FollowerStopper: Safety Analysis and Experimental Results

Chou, Fang-Chieh
Gibson, Marsalis
Bhadani, Rahul
Bayen, Alexandre M.
Sprinkle, Jonathan M.
2021

Motivated by earlier work and the developer of a new algorithm, the FollowerStopper, this article uses reachability analysis to verify the safety of the FollowerStopper algorithm, which is a controller designed for dampening stop-and-go traffic waves. With more than 1100 miles of driving data collected by our physical platform, we validate our analysis results by comparing it to human driving behaviors. The FollowerStopper controller has been demonstrated to dampen stop-and-go traffic waves at low speed, but previous analysis on its relative safety has been limited to upper and lower...

Reduction of Time on the Ground Related to Real-Time Video Detection of Falls in Memory Care Facilities: Observational Study

Bayen, Eleonore
Nickels, Shirley
Xiong, Glen
Jacquemot, Julien
Subramaniam, Raghav
Bayen, Alexandre
2021

Background: Lying on the floor for a long period of time has been described as a critical determinant of prognosis following a fall. In addition to fall-related injuries due to the trauma itself, prolonged immobilization on the floor results in a wide range of comorbidities and may double the risk of death in elderly. Thus, reducing the length of Time On the Ground (TOG) in fallers seems crucial in vulnerable individuals with cognitive disorders who cannot get up independently.
Objective: This study aimed to examine the effect of a new technology called SafelyYou Guardian (SYG) on early...

Multi-Adversarial Safety Analysis for Autonomous Vehicles

Bahati, Gilbert
Gibson, Marsalis
Bayen, Alexandre
2021

This work in progress considers reachability-based safety analysis in the domain of autonomous driving in multi-agent systems. We formulate the safety problem for a car following scenario as a differential game and study how different modelling strategies yield very different behaviors regardless of the validity of the strategies in other scenarios. Given the nature of real-life driving scenarios, we propose a modeling strategy in our formulation that accounts for subtle interactions between agents, and compare its Hamiltonian results to other baselines. Our formulation encourages...

A Rigorous Multi-Population Multi-Lane Hybrid Traffic Model for Dissipation of Waves via Autonomous Vehicles

Kardous, Nicolas
Hayat, Amaury
McQuade, Sean T.
Gong, Xiaoqian
Truong, Sydney
Bayen, Alexandre M.
2022

In this paper, a multi-lane multi-population microscopic model, which presents stop-and-go waves, is proposed to simulate traffic on a ring-road. Vehicles are divided between human-driven and autonomous vehicles (AV). Control strategies are designed with the ultimate goal of using a small number of AVs (less than 5% penetration rate) to represent Lagrangian control actuators that can smooth the multilane traffic flow and dissipate the traffic instabilities, and in particular stop-and-go waves. This in turn may reduce fuel consumption and emissions. The lane-changing mechanism is based on...

Composing MPC with LQR and Neural Network for Amortized Efficiency and Stable Control

Wu, Fangyu
Wang, Guanhua
Zhuang, Siyuan
Wang, Kehan
Keimer, Alexander
Stoica, Ion
Bayen, Alexandre
2022

Model predictive control (MPC) is a powerful control method that handles dynamical systems with constraints. However, solving MPC iteratively in real time, i.e., implicit MPC, remains a computational challenge. To address this, common solutions include explicit MPC and function approximation. Both methods, whenever applicable, may improve the computational efficiency of the implicit MPC by several orders of magnitude. Nevertheless, explicit MPC often requires expensive pre-computation and does not easily apply to higher-dimensional problems. Meanwhile, function approximation, although...