A street-crossing simulator to study the decisions and behaviors of older pedestrians

The aim of the communication is to address the opportunities of a street-crossing simulator to study the decisions and behaviors of older pedestrians in a safe and controlled environment. Older pedestrians are well-known to be over-involved in streetcrossing fatalities. For example, in France, people older than 75 years represent 37% of all pedestrians killed on the road, although they account for less than 9% of the population. For over one decade, pedestrian safety research has investigated age differences in street-crossing behaviors likely to, at least partially, account for the higher crash risk of older pedestrians. But some answers are still lacking and virtual reality can be useful in precisely examining the role of any specific traffic- or pedestrians-related characteristics. The original simulation device includes ten screens (2.55m x 1.88m) forming a corridor in which the pedestrian can actually walk up to 7 meters. The pedestrian's initial position is such that he can watch the traffic coming from both directions by turning his head to the left or right. He is standing at the edge of a sidewalk, facing the experimental street, and has to walk to the other side of the street when he thinks it is safe to do so. The images (60 frames per second) are calculated and projected at the participant’s eye height. Scenes are updated interactively by a movement-tracking system that records the participant’s locomotion (sub-millimeter accuracy) and head motion. A total of 18 young (age 19–35), 28 younger–old (age 62–71) and 38 older–old (age 72-85 years) adults recently participated in an experiment on such a device. The measure of precise behavioral indicators in terms of decision, movement and visual exploration revealed significant differences between the three age groups. The older-old participants crossed more slowly, adopted smaller safety margins, and made more decisions that led to collisions than did the both other groups of participants. Agerelated difficulties were found particularly when vehicles approached rapidly, or in the far lane. The present simulation device allows revealing dangerous attentional deficits as well as physical limitations in older pedestrians. The opportunities of the simulator to also train older people to increase the safety of their behaviors, as well to evaluate the effectiveness of pedestrian navigation aids can be also considered.