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Announcement of PhD Defense : Lama Ayad - Cyclist safety assessment: Risk and behavioral analysis across various infrastructure types and road users’ interactions

Le 10 octobre 2025

Lama Ayad will defend her PhD thesis on 0 October 2025 at 9.00 am

Amphithéâtre Bienvenüe – Bâtiment Bienvenüe

Room B015

Université Gustave Eiffel

12 boulevard Copernic

77420 Champs-sur-Marne

Jury Composition :

rof. Said MAMMAR

Rapporteur

Université d'Évry Paris-Saclay, France

Prof. Giandomenico CARUSO

Rapporteur

Polytechnic of Milan, Italy

Prof. Olivier SENAME

Examinator

Université de Grenoble Alpes, France

Prof. Patricia DELHOMME

Examinator

Université Gustave Eiffel, France

Dr. Michel BASSET

Examinator

Université de Haute Alsace, France

Prof.  Andrea Simone

Invited member

University of Bologna, Italy

Dr. Hocine Imine

Thesis Director

Université Gustave Eiffel, France

Prof. Claudio LANTIERI

Thesis Codirector

University of Bologna, Italy

Prof. Francesca DE CRESCENZIO

Thesis Cosupervisor

University of Bologna, Italy

Abstract:

While cycling as a mode of transport is becoming increasingly popular, cyclists remain among the most vulnerable road users due to their exposure to safety risks and accidents. Assessing these risks and understanding cyclist behavior are essential for improving cyclists' safety and infrastructure design.

This thesis focuses on risk assessment and cyclist behavior by developing a Risk Index (RI) to quantify safety risks across different road segments. This index integrates main factors, including infrastructure characteristics and geometries, cyclist behavior, and external conditions such as traffic and weather. This part followed a multi-phase methodology, including risk factor identification, risk weighting, and risk index formulation.

The second part of the research was based on the evaluation of the risk index using two experiments: a bicycle simulator to assess risk level on simulated road segments and an instrumented bicycle to conduct a real experiment in Bologna, Italy, and assess risk level on different urban road segments. The thesis analyzed the correlation between the RI and subjective feelings of participants to evaluate its reliability, and the methodology used. Furthermore, cyclist behavior, such as gaze metrics and bicycle kinematics, was studied to understand how cyclists interact with different road users and road environments such as intersections, shared roads, crossings, and dedicated cycle paths.

Since sharing cycling infrastructure with pedestrians increases potential conflicts, virtual reality (VR) was used to analyze pedestrian risk perceptions in segments involving interactions with cyclists. A bicycle path from the bicycle simulator was reconstructed in VR and evaluated from the pedestrians' perspective. Comparing cyclist and pedestrian perceptions of shared paths leads to obtaining mutual safety concerns.

Finally, the thesis developed theoretical active safety systems for cyclists, including steering and speed control systems using PID and sliding mode control to reduce lane departures and excessive speeds. Cyclists’ acceptance of these safety assistance tools was also evaluated.

This thesis follows risk assessment methodology for bicycle safety, understands cyclist behavior, and contributes to improving cycling infrastructure planning, promoting safer interactions, and providing active safety solutions to enhance cyclist stability and reduce accidents.