Thesis Defense by Ahmed Yacine LARDJANE

Public-access railroad crossings (TVP), found at nearly 1,000 French train stations, remain a blind spot in scientific research despite efforts to improve railroad safety.

Unlike road level crossings equipped with automatic barriers, TVPs have no physical protection: user safety therefore depends entirely on their ability to correctly perceive the danger and coordinate their actions accordingly.

Our systemic analysis of accidents reveals that perceptual failures are the primary cause of accidents.

This thesis aims to understand the biomechanical mechanisms underlying pedestrian behavior at TVPs and to evaluate the potential of podotactile textures and visual markings to improve pedestrian safety.

The approach is structured around three scientific pillars.

The first, theoretical in nature, concerns the identification of biomechanical parameters relevant to the study of TVPs beyond walking speed alone. It was addressed through a systematic literature review, which provided a solid conceptual and methodological foundation for our subsequent investigations.

The second pillar involved characterizing the locomotor adaptations induced by podotactile textures and their interaction with the geometric constraints of pedestrian traffic zones. The results reveal that the textures induce a significant reduction in walking speed, an improvement in reaction time, and a reorganization of spatiotemporal parameters toward a cautious walking pattern, without disrupting postural balance.

The third challenge focused on the robustness of these effects in an immersive environment replicating the complexity of a real-world TVP.

The results demonstrated a modulation of head rotations and an increase in walking speed during the crossing.

This research establishes an in-depth biomechanical understanding of crossing at level crossings and demonstrates that podotactile textures effectively utilize the somatosensory system to improve safety. It thus paves the way for the development of railway safety equipment centered on natural human capabilities. 

This work shifts the focus of scientific inquiry: rather than limiting itself to the analysis of behavioral outcomes, it examines the perceptual-motor processes that generate them.

Beyond its theoretical contributions, this dissertation provides the scientific community with methodological resources: experimental protocols in natural settings and immersive environments, as well as validated motion analysis tools.

This dissertation lays the groundwork for future research in the field of rail safety and, more broadly, in human-related safety. Keywords: Railroad crossing, safety, motion analysis, perception-action, podotactile textures, biomechanics.

Reviewers

• Anne-Hélène OLIVIER, Associate Professor (HDR), University of Rennes 2
• Thomas ROBERT, Research Fellow (HDR). University of Lyon 1
  

Examiners

• Aurelie DOMMES, Research Director, Gustave EIFFEL University
• Gilles MONTAGNE, University Professor, University of Aix-Marseille
  

Thesis Advisor

• Emilie SIMONEAU, University Professor, UPHF
  

Thesis Co-Advisor:

• Sébastien LETENEUR, University Professor, UPHF
  

Co-supervisors:

• Laura WALLARD, Associate Professor (HDR), UPHF
• Mathias BLANDEAU, Associate Professor, UPHF
  

Guest Member

• Damien HUE, Project Manager, IRT Railenium, Valenciennes

Railway crossings, safety, motion analysis, perception-action, podotactile textures, biomechanics