Analysis of Critical Scenarios of Congestion Emergence and Propagation in Urban Environments

**Analysis of Critical Scenarios of Congestion Emergence and Propagation in Urban Environments**:

- Réf **ABG-131503**
- Sujet de Thèse
- 28/04/2025
- Contrat doctoral
- LICIT laboratory (ENTPE/UGE), Lyon
- Lieu de travail- Lyon - Auvergne-Rhône-Alpes - France
- Intitulé du sujet- Analysis of Critical Scenarios of Congestion Emergence and Propagation in Urban Environments
- Champs scientifiques- Sciences de l’ingénieur
- Physique
- Science de la donnée (stockage, sécurité, mesure, analyse)
- Mots clés- Transport, modeling, artificial intelligence, simulation, traffic theory, civil engineering, mobility, urban planning, transport systems, urban networks

**Description du sujet**:
**Context**

Optimizing transport systems is a key lever for the ecological transition of cities. To reduce their environmental footprint, cities must offer a high-performance multimodal mobility system that ensures safe, rapid, equitable, and low-carbon access to essential services and infrastructures. However, urban congestion represents a major obstacle to these objectives. It generates significant economic, health, and environmental costs, while greatly contributing to air pollution and greenhouse gas emissions.

While the mechanisms of congestion formation and propagation on linear infrastructures (highways, urban corridors) have been extensively studied, the urban context presents specific features that considerably complicate the analysis of this phenomenon. Indeed, the density and heterogeneity of networks, the diversity of demand, and the interdependence with control systems make congestion dynamics particularly difficult to apprehend, even though their effects are critical.

**Subject description**

In this context, LICIT-ECO7 — a joint research unit of ENTPE and Gustave Eiffel University, specialized in transport and energy systems — is offering a PhD position focusing on the identification of key determinants of congestion in urban environments, as well as a detailed understanding of its propagation mechanisms at mesoscopic and macroscopic scales.

Recent research has highlighted the existence of recurrent spatio-temporal patterns in congestion formation. At the macroscopic scale, the MFD (Macroscopic Fundamental Diagram) constitutes a tool for aggregated representation of traffic dynamics within an urban area. By linking the average traffic density to its average flow, it enables characterization of the overall operational state of the network. At a mesoscopic scale, recent studies have aimed to characterize the stability of tree-like congestion structures (or jam trees), revealing persistent congestion propagation properties.

However, although these contributions explore invariants of congestion structures across different cities, they rely on limited historical datasets, which restricts the temporal scope of their conclusions. The recurrence and predictability of congestion emergence at the mesoscopic scale remain insufficiently studied; and the causal chains linking the phases of emergence, propagation, and dissipation of congestion are still poorly characterized. These gaps hinder the development of robust methods for the automatic identification of critical scenarios, particularly cascading failures, whose understanding could enable operational anticipation of major disruption situations. At the same time, the issue of network capacity reserves — meaning segments capable of absorbing or deferring flows during disruptions — remains largely overlooked, even though it constitutes a strategic lever for dynamic and resilient urban mobility management.

This PhD research will aim to address these issues, standing at the crossroads of several methodological approaches. On the one hand, machine learning methods will be used to automatically identify congestion structures. On the other hand, traffic theory, statistical physics (percolation), and artificial intelligence will be leveraged to characterize the underlying propagation phenomena and identify scenarios likely to lead to major system failures. Finally, the use of microscopic and/or macroscopic simulation models will allow exploration of these scenarios and quantification of their impacts on the transport system.

**Prise de fonction**:

- 01/10/2025

**Nature du financement**:

- Contrat doctoral

**Précisions sur le financement**:
**Présentation établissement et labo d'accueil**:

- LICIT laboratory (ENTPE/UGE), Lyon

**The lab**

The LICIT-ECO7 laboratory is a joint research unit under the dual supervision of ENTPE and Gustave Eiffel University. Its research topics address both mobility management and energy management issues within transport systems. The main research areas of LICIT-ECO7 include dynamic modeling, monitoring, and control of mobility networks, as well as the study of the usage, ageing, and control of new vehicles and new components of transport systems.

**Supervision**

Ludovic Leclercq, Professor, Univ. Gustave Eiffel, ENTPE, Lyon

Manon Seppec