Elderly’s heterogeneous responses to topographical factors in travel mode choice within a hilly neighborhood: An analysis based on combined GPS and paper-based surveys

Because of the decline of physical abilities of the elderly, their mobility is more vulnerable to topographical factors than younger population groups. However, topographical factors have been neglected in studies on travel behavior, and elderly people’s heterogeneous responses to topographical factors remain unknown. To fill this research gap, this study focuses on a hilly neighborhood called Koyo Newtown in Hiroshima City, Japan, where a multi-period (two waves) and multi-day (two weeks) panel survey was conducted in 2010 and 2011. The survey consisted of a GPS survey and a paper-based travel diary survey. In addition, a travel mode choice model is developed based on a panel mixed logit model. Heterogeneities are captured by introducing random effects to parameters of topographical factors, which are measured in terms of altitude difference, intensity of up/down movement, maximum slope, and changing slope. Furthermore, effects of introducing personal mobility vehicles (PM) to mitigate negative impacts of topographical factors are also evaluated. As a result, it is found that the altitude difference and maximum slope factors have significant impacts on mode choice decisions. The effectiveness of PM to support the mobility of elderly residents is also confirmed.