Relationship between gaze behavior and whole-body movement during car ingress

Abstract

Car ingress and egress are the most physically demanding activities in car use, particularly for older people with weak muscles. In a survey of elderly people in Japan regarding car use, the load on the legs and back during ingress and egress was ranked at the top of complaint. Reducing the load during car ingress and egress will make it easier for older people to use cars and is expected to contribute to maintaining and improving the quality of life for aging societies. Many studies regarding car ingress and egress have mainly focused on the motion analysis of the whole-body movement. However, the movement needs to be modified in response to the visual information regarding the spatial relationship between a narrow space of the car entrance and the body. We therefore investigated in the present study the relationship between gaze behavior and whole-body movement during car ingress. Based on the findings, we discussed whether patterns of whole-body movement to enter the car are related at least in part to how individuals look at the car entrance.12 young adults between the ages of 18 and 21(Mean =20.2, SD=0.94; 2 women and 10 men) participated. A mock-up of a car with doors was used to measure the gaze behavior and whole-body movement. There were two roof height conditions: high (1500 mm from the floor) and low (1330 mm). Gaze behavior was measured using a Pupil Labs eye tracker, while whole-body movement was measured using a Qualisys motion capture system capturing 25-point markers attached to the participant’s whole body. For the gaze behavior, fixated locations were categorized into one of four locations: roof area, door area, floor area, and other in cabin. The results of the cluster analysis using the total time spent gazing at each fixated location showed three main groups of gaze patterns. The first group was characterized with looking mostly on the floor, possibly perceiving the car entrance with the peripheral vision. The participants categorized in the first group tended to show bending the upper body in a forward-leaning position. The second group was characterized with looking around the area surrounded with the roof and door. The participants categorized in this group leaned their upper body backward when entering the car. The participants categorized into third group kept looking at the floor (i.e., with longer fixation time) bended the upper body in a sideways-leaning position. These findings suggest that patterns of whole-body movement to enter the car are related at least in part to the gaze behavior. The findings also suggest that technologies or other means that lead the car-user’s fixations in proper location will help not only to avoid collisions with the car frames but also to reduce the load of car ingress.

Keywords: Car Ingress, Gaze Behavior, Whole-Body Movement

DOI: 10.54941/ahfe1005225