| Summary: | Visual information plays an important role for walking in the footway environment as an essential daily activity. Visual perception of the uneven footway surface is the experience that allows us to detect and understand potential hazards and negotiate obstacles along the way when we walk. In order for people to adjust their gait properly to cope with small changes in the footway surface, the primary essential process is to see and understand the detail of such changes in time for the adjustment to be made to avoid or step over the changes. A fall is likely to occur if the change in height is not as perceived and expected and the subsequent misplacement of the foot may be unexpectedly striking a surface or experiencing the absence of an expected surface. The purpose of this study is to investigate the relationships between the physical environment and visibility of unevenness in the footway surface to people with different capability, especially to elderly people. Therefore, this thesis concerns the initial phase of dealing with unevenness in the footway surface, which is to determine how well older people can see and understand small changes in the footway surface, by running behavioural experiments and conducting psychophysical measures in the UCL Pedestrian Accessibility and Movement Environment Laboratory (PAMELA) where lighting and surface conditions were controlled. I found that the lighting level and the pattern of the unevenness as physical properties of the footway environment and the visual abilities of the participants influence people’s visual perception of uneven surface and their gaze behaviours during the course. The older participants made more incorrect judgements on the footway surfaces and were more likely to misperceive the unevenness with low height level compared with young people, especially at the mesopic luminance level. Some patterns of the unevenness and the visual abilities could affect the height estimation consistently regardless of the lighting level and age group. The findings of this thesis could help ophthalmological clinicians develop targeted fall preventions and help urban planners and local authorities to design and maintain the footway environment to reduce the risk of fall or tripping.
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