Qichao (Leo) Liu

Qichao (Leo) Liu

Currently, I am a postdoc fellow at the Hong Kong Polytechnic University, specializing in autonomous driving.

Publications

You can also find my articles on my Google Scholar profile.

Single-Layer Efficient Optimization for Right-of-Way and Trajectory Control of Connected and Autonomous Vehicles at Signalized Intersections

Published in Journal of Transportation Engineering, Part A: Systems, 2026

A single-layer efficient optimization framework for right-of-way allocation and trajectory control of connected and autonomous vehicles at signalized intersections. Accepted by Journal of Transportation Engineering, Part A: Systems.

Recommended citation: Q. Liu, H. Zhou, J. Huo, and C. Ma. "Single-Layer Efficient Optimization for Right-of-Way and Trajectory Control of Connected and Autonomous Vehicles at Signalized Intersections." Journal of Transportation Engineering, Part A: Systems, accepted. https://doi.org/10.1061/JTEPBS.TEENG-9210

Distributed two-dimension model predictive control for left-turn control of connected and automated vehicle platoons at signalized intersections

Published in Transportation Research Part E: Logistics and Transportation Review, 2026

A distributed 2D MPC framework for left-turn control of connected and automated vehicle platoons at signalized intersections.

Recommended citation: Q. Liu and J. Wang. (2026). "Distributed two-dimension model predictive control for left-turn control of connected and automated vehicle platoons at signalized intersections" Transportation Research Part E: Logistics and Transportation Review, 212, 104954. https://doi.org/10.1016/j.tre.2026.104954

REACT: Runtime-Enabled Active Collision-Avoidance Technique for Autonomous Driving

Published in Advanced Engineering Informatics, 2026

A lightweight closed-loop framework for runtime risk assessment and active collision avoidance in autonomous driving.

Recommended citation: H. Huang, H. Cheng, Z. Zhou, Z. Wang, H. Wang, Q. Liu, and X. Li. (2026). "REACT: Runtime-Enabled Active Collision-Avoidance Technique for Autonomous Driving." Advanced Engineering Informatics, 71, 104248. https://doi.org/10.1016/j.aei.2025.104248

Aggressiveness-conservativeness trade-off in cooperative driving: An adaptive CBF approach under perception constraints

Published in Transportation Research Part C: Emerging Technologies, 2026

An adaptive CBF-based cooperative driving framework that balances safety and efficiency under perception constraints.

Recommended citation: Q. Liu and J. Wang. (2026). "Aggressiveness-conservativeness trade-off in cooperative driving: An adaptive CBF approach under perception constraints." Transportation Research Part C: Emerging Technologies, 183, 105435. https://doi.org/10.1016/j.trc.2025.105435

Integrated Spatiotemporal Resource and Vehicle Coordination for Optimizing Signal Control Intersection Performance

Published in , 2026

A coordinated optimization framework for spatiotemporal resource allocation and vehicle coordination at complex signalized intersections. Under review at IEEE Transactions on Vehicular Technology.

Recommended citation: Q. Liu, J. Wang, D. Ngoduy, X. Hua, and W. Wang. "Integrated Spatiotemporal Resource and Vehicle Coordination for Optimizing Signal Control Intersection Performance." Under review at IEEE Transactions on Vehicular Technology.

Model Predictive Control for Coordinated Lane Assignment and Longitudinal Coordination in Intersection Lane Expansion Zones

Published in 2025 IEEE 28th International Conference on Intelligent Transportation Systems (ITSC), 2025

An MPC-based strategy for coordinated lane assignment and longitudinal coordination of CAVs in intersection lane expansion zones.

Recommended citation: Q. Liu, D. Ngoduy, W. Yu, and J. Wang. (2025). "Model Predictive Control for Coordinated Lane Assignment and Longitudinal Coordination in Intersection Lane Expansion Zones." 2025 IEEE 28th International Conference on Intelligent Transportation Systems (ITSC), 2776–2780. https://doi.org/10.1109/ITSC60802.2025.11423429

Fair and Safe: A Real-Time Hierarchical Control Framework for Intersections

Published in arXiv preprint, 2025

A fairness-aware real-time hierarchical control framework for connected and automated vehicles at intersections. Under review at IEEE Transactions on Intelligent Transportation Systems.

Recommended citation: L. Shi, Y. Kim, X. Zhong, W. Kontar, Q. Liu, and S. Ahn. (2025). "Fair and Safe: A Real-Time Hierarchical Control Framework for Intersections." arXiv preprint, arXiv:2511.05886. Under review at IEEE Transactions on Intelligent Transportation Systems. https://arxiv.org/abs/2511.05886

RiskNet: Interaction-Aware Risk Forecasting for Autonomous Driving in Long-Tail Scenarios

Published in Transportation Research Part E: Logistics and Transportation Review, 2025

An interaction-aware risk forecasting framework for autonomous driving in long-tail scenarios, integrating deterministic risk modeling with probabilistic behavior prediction.

Recommended citation: Q. Liu, H. Huang, S. Zhao, L. Shi, S. Ahn, and X. Li. (2025). "RiskNet: Interaction-Aware Risk Forecasting for Autonomous Driving in Long-Tail Scenarios." Transportation Research Part E: Logistics and Transportation Review, 205, 104478. https://doi.org/10.1016/j.tre.2025.104478

An unstructured single-layer optimization approach for flexible right-of-way allocation and cooperative trajectory planning at signalized intersections

Published in Computer-Aided Civil and Infrastructure Engineering, 2025

An unstructured single-layer optimization framework for flexible right-of-way allocation and cooperative trajectory planning at signalized intersections.

Recommended citation: Q. Liu, Z. Huang, Z. Sheng, and S. Chen. (2025). "An unstructured single-layer optimization approach for flexible right-of-way allocation and cooperative trajectory planning at signalized intersections." Computer-Aided Civil and Infrastructure Engineering, 40(19), 2793–2815. https://onlinelibrary.wiley.com/doi/full/10.1111/mice.13481

A Fairness-Oriented Control Framework for Safety-Critical Multi-Robot Systems: Alternative Authority Control

Published in 2025 IEEE International Conference on Robotics and Automation (ICRA), 2025

A fairness-oriented control framework for safety-critical multi-robot systems based on AAC and F-CBF.

Recommended citation: L. Shi, Q. Liu, C. Zhou, and X. Li. (2025). "A Fairness-Oriented Control Framework for Safety-Critical Multi-Robot Systems: Alternative Authority Control." 2025 IEEE International Conference on Robotics and Automation (ICRA), 16283–16289. https://doi.org/10.1109/ICRA55743.2025.11127533

Real-Time Cooperative Optimization of Right-of-Way Allocation and Two-Dimensional Trajectories for Connected and Automated Vehicles at Signal-Free Intersections

Published in , 2025

A real-time cooperative optimization framework for right-of-way allocation and two-dimensional trajectory planning of connected and automated vehicles at signal-free intersections. Under review at Transportation Research Part B: Methodological.

Recommended citation: Q. Liu, J. Wang, and Z. Liu. "Real-Time Cooperative Optimization of Right-of-Way Allocation and Two-Dimensional Trajectories for Connected and Automated Vehicles at Signal-Free Intersections." Under review at Transportation Research Part B: Methodological.

Cooperative Longitudinal Driving and Lane Assignment Strategy for Left-Turn Connected and Autonomous Vehicles at Signalized Intersections With a Contraflow Left-Turn Lane

Published in IEEE Transactions on Intelligent Transportation Systems, 2024

A cooperative control strategy for longitudinal driving and lane assignment of left-turn CAVs at signalized intersections with a contraflow left-turn lane.

Recommended citation: Q. Liu, J. Wang, W. Wang, X. Hua, and Y. Du. (2024). "Cooperative Longitudinal Driving and Lane Assignment Strategy for Left-Turn Connected and Autonomous Vehicles at Signalized Intersections With a Contraflow Left-Turn Lane." IEEE Transactions on Intelligent Transportation Systems, 25(11), 17614–17627. https://doi.org/10.1109/TITS.2024.3416442

Optimal Trajectory Control for Left-Turn Vehicles at Exit Lane for Left-Turn Intersections

Published in Journal of Transportation Engineering, Part A: Systems, 2021

A mixed-integer trajectory control model for left-turn vehicles at EFL intersections under automated driving.

Recommended citation: Q. Liu, J. Zhao, and X. Zhou. (2021). "Optimal Trajectory Control for Left-Turn Vehicles at Exit Lane for Left-Turn Intersections." Journal of Transportation Engineering, Part A: Systems, 147(10), 04021056. https://ascelibrary.org/doi/full/10.1061/JTEPBS.0000576

Modeling the Operation of Left-Turn Vehicles at Exit Lanes for Left-Turn Intersections

Published in Journal of Transportation Engineering, Part A: Systems, 2021

A microscopic traffic flow model for analyzing left-turn vehicle operations at exit lanes for left-turn intersections.

Recommended citation: Q. Liu, X. Zhou, and J. Zhao. (2021). "Modeling the Operation of Left-Turn Vehicles at Exit Lanes for Left-Turn Intersections." Journal of Transportation Engineering, Part A: Systems, 147(5), 04021022. https://ascelibrary.org/doi/abs/10.1061/JTEPBS.0000520