Haptic feedback for improved safety of elderly e-bike users in V2X urban environments

Abstract

This graduation project explored how haptic feedback could be adapted to communicate navigation and safety cues with minimal distraction, enhancing the road user’s perception and response in mixed urban traffic scenarios. A key area of investigation of the project was to improve the ease of use, intuitiveness and (perceived) safety for the elderly (e-)bike users. The challenge lied in understanding how such feedback could be integrated effectively into the cycling experience and in defining what makes cues clear, distinguishable, and context appropriate. The project is designed towards the future vision, on an urban scenario, in which low-traffic policies and active mobility have been further developed and in which digital infrastructure is broader integrated into the transport systems, which means that vehicles, infrastructure and users have increasingly become part of an interconnected ecosystem.

The design resulted in a directional haptic interface with two contact points: the helmet and the handles. The helmet is used for spatial feedback around the head, and the handles for local directional cues in the hands. Together, they form one connected warning system. The system is translated into a prototype, that includes a haptic helmet, head tracking, vibrating handles, a link between bicycle and helmet, a simulated digital test environment, a web-based interface and a fixed-base simulator for controlled user testing.

This project was carried out using the Double Diamond model, comprising the phases of Discovery, Definition, Development and Delivery, and was concluded with a design evaluation. The process began with a context analysis, followed by the formulation of the problem statement. The vision was then defined based on design principles, success criteria, scope and conceptual direction. In the final phase, the design was worked out in detail. A helmet module and a handlebar module were built, including microcontrollers, vibration motors, haptic drivers, IMUs, batteries, and wireless communication between bicycle and helmet. A handle prototype was developed through 3D scanning, digital modelling, 3D-printing, and material testing. Finally, a software architecture was developed to connect the simulator, server, gateway, handle node, and helmet node. This made it possible to play traffic scenarios, trigger warnings, and translate bicycle-based hazard data into rider-based haptic feedback.

User testing was conducted to evaluate whether directional haptic feedback via vibrating handles and a vibrating helmet would be experienced as an acceptable interaction modality in a desktop-based simulated cycling context, with specific attention to workload, usefulness, satisfaction, clarity/interpretability and perceived safety/irritation.

The user evaluation showed that directional haptic feedback has clear potential as an interaction modality for cycling-related hazard warnings. The prototype was generally experienced as useful, reasonably satisfying and not overly demanding. The helmet performed best in terms of directional clarity and interpretability, while the handles offered more practical appeal but weaker interpretative performance. It shows that the central challenge is not only technical feasibility, but the translation of connected traffic information into a warning that is supportive, acceptable, and behaviourally appropriate.