Differences in choice of transportation mode by residents of 15-minute cities according to destination amenities: Break away from car dominant city

• Overall, 15-minute city residents tend to avoid car use. • More than 70% of 15-minute city residents still use cars. • People in low-population-density areas are significantly more likely to use cars. • People who have higher incomes are significantly more likely to use cars. The 15-minute city is an urban design concept that promotes access to amenities and services within 15 min of one’s home, aiming to reduce environmental impact and improve health. However, even if proximity is achieved, residents do not always choose to use active transport modes such as walking or cycling, and car dependency could undermine the goal of creating a healthy and environmentally friendly society. This study explored the transition from an “accessible” 15-minute city to a “carless” 15-minute city, with a focus on understanding why residents still use cars despite proximity to amenities and how that proximity influences transport mode choices. An original survey of walking times and transportation choices in several regions of Japan was conducted, focusing on key amenities such as grocery stores, health care, and financial services. Two logit models were used: one analyzed overall trends in transportation mode choice of all respondents ( n = 975), and the other focused on residents of a “sufficient” 15-minute city ( n = 197) who can reach all 3 amenities within a 15-minute walk from their home. Factors such as proximity, population density, and income were included in the models. In the first logit model, shorter distances to amenities increased the likelihood of walking or cycling. However, the second model revealed that over 70 % of residents still used cars despite proximity to amenities, although lower-income groups were more likely to walk or cycle. Population density and income levels were significant factors in both models, but land-use diversity had little effect on transportation mode choice. To achieve a “carless” 15-minute city, all necessary amenities should be close to residential areas, but it is also important from a policy standpoint to increase population density and implement more comprehensive urban planning strategies.