Exterior Human-Machine Interface
The Effect of an Exterior Human-Machine Interface on a Travelling Cyclist
Motivation:
An exterior lighting system was proposed to display warnings on the surface of the road to attract the attention of cyclists. By displaying warning signals which can easily be understood, cyclists can be informed about the future movement and actions of vehicles, even when they are not paying attention to the vehicles. A field experiment was performed to investigate the influences of the system on the behaviour of cyclists.
Project description:
The proposed exterior lighting system can display different kinds of warning signals in different situations. Normally, when a parked vehicle is involved, a conflict between the vehicle and a cyclist may occur in a scenario in which the cyclist is approaching from behind while the driver is getting out, and the cyclist may collide with the opening door.
To avoid a collision between the cyclist and the opening door, when a driver is trying to get out a warning signal will be displayed from the side mirror of the vehicle onto the road to signal that the door will soon be opening. Two approaches were devised to display the warning signal. One displays the full warning signal as a flashing light. The other shows the warning signal more gradually, as an animation which shows the door opening. It is anticipated that the cyclist will quickly judge the movement of the vehicle with this exterior lighting system, even when they are not actually looking at the vehicle, which may improve traffic safety as a result.
For any newly proposed assistance system, one of the essential tasks is to evaluate the effectiveness of the system through human behaviour analysis. A field experiment was therefore carried out to evaluate the influence of the exterior lighting system on the behaviour of cyclists, and the study received approval from the Ethical Examination Committee of the Office of Life Science Research Ethics and Safety at The University of Tokyo.
Twelve participants attended the experiment, half of whom had a driving licence. They were asked to ride along a white line from a starting point. To make the experiment realistic, a team member rode behind the participants. When the participants were 20 metres away from the vehicle equipped with the system, the warning signal was displayed on the road surface. Several situations were prepared for every participant, including a dummy situation in which the door would not be opening, and no warning signal displayed, and a situation in which the door would be opening while no warning signal was displayed. For the flashing approach, the door would be opening and the warning signal would be displayed as a flashing light, while for the animation approach, the door would be opening and the signal would be shown as an animation.
Conclusion:
It was observed that the distance that cyclists could be from the opening door and still be aware of the hazard could be significantly increased when the warning signal was displayed as an animation, compared to the situation in which no warning signal was provided. The results indicate that traffic safety may be improved by applying the proposed system.
For future implementation, it is still necessary to ensure that the exterior lighting system is not only effective but also that it will not result in unexpected accidents, according to the requirements of ISO/TR 23049.
Team members:
Bo Yang
Research Associate, Institute of Industrial Science, The Univ. of Tokyo
Jieqing Ning
Graduate Student, Institute of Industrial Science, The Univ. of Tokyo
Kimihiko Nakano
Professor, Institute of Industrial Science, The Univ. of Tokyo
Munetaka Nishihira
Mitsubishi Electric Corporation