Dynamic Decisions and Temporal Frictions in On-Demand Mobility
Event details
| Date | 22.06.2026 |
| Hour | 10:30 › 11:30 |
| Speaker | Dr Andrés Fielbaum |
| Location | |
| Category | Conferences - Seminars |
| Event Language | English |
ABSTRACT
App-based, on-demand transport systems have transformed urban mobility by enabling real-time coordination between vehicles and users. Yet behind this flexibility lies a fundamental tension: operational decisions that appear beneficial in the present can deteriorate the future state of the system. This talk explores these temporal frictions in assigned on-demand systems—where passengers and vehicles are matched before meeting—and how they shape the performance and reliability of shared mobility services.
First, we show how assignment decisions evolve through what we term the Increasing Gap Dynamics, a negative feedback cycle through which vehicles progressively concentrate in space, reducing system efficiency over time. We then examine how a tension between efficiency and reliability emerges: while highly dynamic operations can improve short-term efficiency and flexibility, they may also increase unreliability by exposing passengers to future, uncertain requests. We discuss how this tension manifests both in routing decisions and in the selection of pickup and dropoff locations, and show how carefully designed anticipatory techniques can help reconcile these competing objectives.
SHORT BIO
Dr Andrés Fielbaum is a Senior Lecturer in Transport Engineering at the University of Sydney and a DECRA Fellow of the Australian Research Council. His work lies at the intersection of transport systems and applied mathematics, with a focus on public transport, on-demand mobility, and developing analytical models to inform system design and operations. He completed his PhD in Systems Engineering at Universidad de Chile in 2019 and held a postdoctoral appointment at TU Delft between 2019-2023.
Dr Fielbaum has authored over 35 peer-reviewed journal articles in leading outlets and serves as an Associate Editor for Transportation Research Part B: Methodological, and the Journal of Intelligent Transportation Systems.
App-based, on-demand transport systems have transformed urban mobility by enabling real-time coordination between vehicles and users. Yet behind this flexibility lies a fundamental tension: operational decisions that appear beneficial in the present can deteriorate the future state of the system. This talk explores these temporal frictions in assigned on-demand systems—where passengers and vehicles are matched before meeting—and how they shape the performance and reliability of shared mobility services.
First, we show how assignment decisions evolve through what we term the Increasing Gap Dynamics, a negative feedback cycle through which vehicles progressively concentrate in space, reducing system efficiency over time. We then examine how a tension between efficiency and reliability emerges: while highly dynamic operations can improve short-term efficiency and flexibility, they may also increase unreliability by exposing passengers to future, uncertain requests. We discuss how this tension manifests both in routing decisions and in the selection of pickup and dropoff locations, and show how carefully designed anticipatory techniques can help reconcile these competing objectives.
SHORT BIO
Dr Andrés Fielbaum is a Senior Lecturer in Transport Engineering at the University of Sydney and a DECRA Fellow of the Australian Research Council. His work lies at the intersection of transport systems and applied mathematics, with a focus on public transport, on-demand mobility, and developing analytical models to inform system design and operations. He completed his PhD in Systems Engineering at Universidad de Chile in 2019 and held a postdoctoral appointment at TU Delft between 2019-2023.
Dr Fielbaum has authored over 35 peer-reviewed journal articles in leading outlets and serves as an Associate Editor for Transportation Research Part B: Methodological, and the Journal of Intelligent Transportation Systems.
Practical information
- Informed public
- Free
Organizer
- HOMES - Prof. Kenan Zhang
Contact
- Prof. Kenan Zhang
Administrative: Mélanie Thuillard