Navigation and the ageing driver

This thesis examines issues surrounding route navigation. Emphasis is on the problems of elderly motorists. Elderly drivers have been said to avoid unfamiliar routes and may have wayfinding problems, but the extent and nature of these problems have not previously been investigated. This thesis aims to determine how drivers plan their routes and find their way in transit. It also seeks to investigate the prevalence and types of driver wayfinding problems, as well as their causes, consequences and psychological implications. Lastly, this thesis aims to measure the impact wayfinding problems have on mobility and identify potential solutions. Three studies were conducted, the first was a preliminary investigation into route navigation issues. Focus group discussions explored driver wayfinding strategies and problems. The second study consisted of a postal questionnaire survey of motorists. Results suggested the most common route planning method was to read a map and take notes of the route. For wayfinding on major roads, drivers stated a preference for road number, place name, and junction information. In cities, they requested information about street names, lane position and landmarks. More drivers under 60 years of age preferred landmark information than did elderly drivers. The most frequent wayfinding errors were: missing a road sign, choosing the wrong lane, and detecting a sign or a turn too late to respond safely. The most frequently reported causes of wayfinding errors were: insufficient, inaccurate, obscured or non-existent traffic signs; inattention or distraction; inaccurate directions; darkness; busy roads and road repairs. As hypothesised, elderly drivers reported more difficulties with wayfinding and this was related to reduced mobility. The third study explored different means of presenting route guidance information. An experiment was conducted to investigate the safety and efficiency of visual, auditory (speech) or a combined visual-auditory display. Driver performance, visual behaviour, subjective mental workload and preferences were recorded. For displaying simple route guidance information to drivers across ages, it is recommended that verbal displays be used as a primary source of guidance information and visual displays as a redundant reminder.