SMRT - Ifsttar

7 Decembre 2023

14h00	Pravesh BIYANI, Associate Professor at IIIT Delhi, Founder of Anamar Tech.
	No Transfers Required: Integrating Last Mile with Public Transit Using Opti-Mile.
	Abstract: Public transit is a popular mode of transit due to its affordability, despite the inconveniences due to the necessity of transfers required to reach most areas. For example, in the bus and metro network of New Delhi, only 30% of stops can be directly accessed from any starting point, thus requiring transfers for most commutes. Additionally, last-mile services like rickshaws, tuk-tuks or shuttles are commonly used as feeders to the nearest public transit access points, which further adds to the complexity and inefficiency of a journey. Ultimately, users often face a tradeoff between coverage and transfers to reach their destination, regardless of the mode of transit or the use of last-mile services. To address the problem of limited accessibility and inefficiency due to transfers in public transit systems, we propose ``opti-mile," a novel trip planning approach that combines last-mile services with public transit such that no transfers are required. Opti-mile allows users to customize trip parameters such as maximum walking distance, and acceptable fare range. We analyse the transit network of New Delhi, evaluating the efficiency, feasibility and advantages of opti-mile for optimal multi-modal trips between randomly selected source-destination pairs.

14h45	Benoit MATET, COSYS/GRETTIA lab. University Gustave Eiffel.
	Use of Origin-Destination data for calibration and spatialization of activity based models.
	Abstract: Mobile phone data are a good source to estimate aggregated travel demand. In this work, we investigate how Origin-Destination (OD) matrices from mobile phone data can be used along with Household Travel Surveys (HTS) to synthesise comprehensive travel demand that is both detailed at the individual leve and calibrated to what is observed from mobile data. We propose a calibration step and a spatialisation step that can be added to the already existing state-of-the-art pipelines, which can improve the realism of synthetic travel demand when the OD matrices are assumed of good quality. Our approach can also measure the incompatibilities between the HTS and the mobile data that are known to exist but hard to quantify.

14h45	Sarah GASMI, COSYS/GRETTIA lab. University Gustave Eiffel.
	Multi-class traffic carbon abatement via speed limit optimization.
	Abstract: As the urgency to mitigate climate change intersects with the need for efficient transportation systems, innovative traffic management strategies become crucial. This talk will delve into the challenge of devising traffic management strategies aimed at carbon abatement within the complex dynamics of a multi-modal road network. Our objective is to strike a critical balance between environmental sustainability and economic viability. The strategy centers on managing traffic via speed limit control to concurrently optimize the total travel time for users and minimize carbon emissions. Our methodology employs a Mixed-Integer Linear Programming (MILP) formulation to address this multi-class, bi-objective network problem under a series of constraints. Initially, we tackle the User Equilibrium (UE)-based traffic assignment , progressing to incorporate the Boundedly Rational User Equilibrium (BRUE), which introduces a layer of flexibility in the system. A key innovation in our approach is the consideration of free-flow speed as a decision variable within both UE and BRUE frameworks. The practicality of our model is underscored by its application to the transportation network of Tilburg, The Netherlands. This case study exemplifies the real-world implications and potential of our approach. By exploring this model, we aim to contribute to the development of traffic management systems that are both eco-friendly and economically sound, paving the way for smarter, sustainable urban mobility solutions.

13 sept 2023

14h00	Professor Elise Miller-Hooks, Professor & Hazel Chair in Infrastructure Engineering Interim Department Chair, Sid & Reva Dewberry Department of Civil, Environmental, and Infrastructure Engineering, George Mason University.
	Optimization and Machine Learning in Urban Transportation Under a Sharing Economy.
	Abstract: As our cities grow, competition for staff (workers), stuff (equipment, such as cars) and space (location, e.g. parking) grows, and greater efficiencies in resource (staff and stuff) and space utilitization in the context of transportation services are required to support vibrant local economies. On-line, optimization and machine learning can aid in the creation of new transportation markets and services, as well as new service mechanisms for existing services (e.g. equitable microtransit services), and, off-line, can inform urban transportation planning and policy. This talk will describe mathematical, algorithmic, and machine learning methods that exploit the sharing economy in designing and operating such urban transportation services in dense, competitve urban environments. Applications specific to bicycle and carsharing, ridesharing, parking, and delivery will be described.

15h30	Café et Discussion.

Short Bio: Dr. Elise Miller-Hooks holds the Bill and Eleanor Hazel Endowed Chair in Infrastructure Engineering and is the Interim Department Chair of the Sid & Reva Dewberry Department of Civil, Environmental, and Infrastrucure Engineering at George Mason University. She has served as an advisor to the World Bank Group and is the founding Editor-in-Chief of Elsevier’s Sustainability Analytics and Modeling journal. Prior to her appointment at Mason, Dr. Miller-Hooks served as a program director at the U.S. National Science Foundation and on the faculties of the University of Maryland, Pennsylvania State University and Duke University. Dr. Miller-Hooks received her Ph.D. (1997) and M.S. (1994) degrees in Civil Engineering from the University of Texas – Austin and B.S. in Civil Engineering from Lafayette College (1992). She has expertise in: real-time routing and fleet management, including paratransit, ridesharing, bikeways and delivery; disruption planning and response; multi-hazard civil infrastructure resilience quantification and protection; stochastic and dynamic network algorithms; transportation systems engineering; intermodal passenger and freight transport; hospital capacity planning for surge; and collaborative and multi-objective decision-making.

29 juin 2023

14h00	Dr. Hossein Nick Zinat Matin, University of California at Berkeley.
	Some complexities in traffic dynamics: from wave interactions in macroscopic models in the presence of bottleneck to boundary-layer analysis in car-following models.
	Abstract: In this talk, we start with some results in macroscopic traffic flow dynamics. In particular, we discuss a PDE-ODE Cauchy problem in the presence of bottlenecks and under some conditions on the flux functions. In particular, we discuss the wave interactions in this case and talk through the complications that arise as a result of such interactions. Such understanding is essential in both proving the existence and uniqueness of the solution as well as designing efficient numerical schemes. Then, if time allows, we will discuss a boundary layer analysis of optimal velocity follow- the-leader dynamics in microscopic traffic flow. We rigorously study the behavior of the dynamics near collision in a deterministic case. We will also introduce stochasticity in the dynamic model and study the trade-off between noise and collision.

15h30	Café et Discussion.

Short Bio: Hossein is currently a postdoctoral researcher with Dr. Delle Monache’s lab at the University of California at Berkeley. Prior to that, he was an adjunct professor at the University of Illinois at Urbana Champaign where he earned his master’s and Ph.D. degrees in pure mathematics and system engineering. Hossein is interested in studying the hyperbolic and parabolic PDE problems that mainly arise in applications such as traffic flow and fluid dynamics.

9 Mars 2023

14h00	Prof. Nikolas Geroliminis, EPFL.
	Macroscopic modeling and control of multimodal systems.
	Abstract: Human mobility in congested city centers is a complex dynamical system with high density of population, many transport modes to compete for limited available space and many operators that try to efficiently manage different parts of this system. The primary motivation of this talk is to study the spatiotemporal relation of congested links in large networks, develop new advancements in the Macroscopic Fundamental Diagram, observe congestion propagation from a macroscopic perspective, identify the effect of multimodal interactions in network capacity and finally design hierarchical network-level control strategies to improve multimodal mobility. Different control strategies are developed based on the principles of optimization control theory.

14h45	Café et Discussion.

15h15	Prof. Nikolas Geroliminis, EPFL.
	Aggregated Modeling and Smart operations of on-demand transportation systems.
	Abstract: Dynamic network-level models directly addressing ride-sourcing services can support the development of efficient strategies for both congestion alleviation and promotion of more sustainable mobility. Recent developments presented models focusing on ride-hailing (solo rides), but no work addressed ride-splitting (shared rides) in dynamic contexts. Here, we sought to develop a dynamic aggregated traffic network model capable of representing ride-sourcing services and background traffic in a macroscopic multi-region urban network. We combined the Macroscopic Fundamental Diagram (MFD) with detailed state-space and transition descriptions of background traffic and ride-sourcing vehicles in their activities to formulate mass conservation equations. We will also develop different rebalancing strategies that can move vehicles with no passengers to regions of higher attraction to improve the quality of service.

Bio: Prof. Nikolas Geroliminis is a Full Professor at EPFL and the head of the Urban Transport Systems Laboratory (LUTS). Before joining EPFL he was an Assistant Professor on the faculty of the Department of Civil Engineering at the University of Minnesota. He has a diploma in Civil Engineering from the National Technical University of Athens (NTUA) and a MSc and Ph.D. in civil engineering from University of California, Berkeley. His research interests focus primarily on urban transportation systems, traffic flow theory and control, public transportation and on-demand transport, car sharing, Optimization and Large Scale Networks. He is a recipient of the ERC Starting Grant METAFERW: Modeling and controlling traffic congestion and propagation in large-scale urban multimodal networks. Among his recent initiatives is the creation of an open-science large-scale dataset of naturalistic urban trajectories of half a million vehicles that have been collected by one-of-a-kind experiment by a swarm of drones (https://open-traffic.epfl.ch). Among other editorial responsibilities, he is currently the Editor-In-Chief of Transportation Research part C: Emerging Technologies.