A tale of two aging nations: How do urban designs impact older adults’ mobility in automobile versus transit societies?

• Examined older adults’ mobility in two fast-aging countries: the U.S. and Japan. • Analyzed the influence of built environments in automobile and transit societies. • Fill the research gap in the impact of automobile-oriented culture on older adults’ mobility. • In a transit society, compact designs encouraged older people to be more active. • In an automobile society, household vehicle and driver license had dominating influences on older adults’ mobility. Sustainability strategies have called for dense and accessible neighborhood designs to facilitate convenient access to desirable destinations for all, with a particular attention to transportation-disadvantaged populations such as older adults (aged 65 and older). However, few studies have examined and compared whether compact designs could help address the mobility needs of older people in automobile- and transit-oriented societies, even though aging populations are growing substantially. We analyze the travel and activity behaviors of older adults living in areas with completely different urban and transportation paradigms, the United States and Tokyo, Japan, based on the 2017 National Household Travel Survey and the 2018 Tokyo Person Trip Survey. After we account for the potential residential selection bias, we find that older people living in denser and more accessible environments in transit societies in Tokyo, Japan tended to conduct more active and transit tours but fewer automobile tours and shorter travel. Moreover, these older adults were more likely to be engaged in social, shopping, and recreational activities. For their counterparts in the U.S., built environments were found to have moderate impacts, but the possession of driver license and household vehicles showed greater explanatory power, which could be related to the country’s automobile-oriented culture. Our results suggest that dense and accessible neighborhood designs can enhance older people’s mobility with more out-of-home activities, but the influences of the macro-regional contexts and automobile-oriented culture should be cautiously taken into account.