The 15-minute city for all? – Measuring individual and temporal variations in walking accessibility

Abstract

Popular concepts in urban planning, like the 15-minute city, suggest that everyday services should be accessible to everyone within “walking distance”. However, walking distance is usually considered from the perspective of the average person, and little effort is made to understand the temporal (daily and seasonal) variation in walking accessibility. If our aim is to create inclusive cities, we also need to address the realities of vulnerable population groups.In this study, we analysed how walking accessibility landscapes vary temporally and between population groups particularly focusing on the diverse realities of older people. We hypothesised that the temporal variation, especially seasonal, disproportionately influences their range of mobility options. To test this, we first recorded walking speeds in Finland’s Helsinki Metropolitan Area during dry and winter season. We then created and compared accessibility landscapes between groups with different walking characteristics by integrating data on seasonal walking speeds, diurnal activity opening hours, and the (residential) locations of people.We showed that the diurnal variation has the largest effect on walking accessibility in the study area over seasonal and age-related variation when these variables are considered separately. Combined, these variations can explain reductions in accessibility that, in the worst-case scenario result in only 34% of the older population having 15-minute walking access to the closest grocery shop, compared to a baseline of 93%. However, the intra-group variation between population groups and road conditions remains large.The study highlights the importance of considering the variation in people’s walking abilities, road conditions and service network when modelling walking accessibility. This is particularly important for vulnerable population groups, such as older people, who often rely on running errands on foot and may have impaired mobility. The results support spatial planners to mitigate social and spatial inequalities and help them to promote environmentally sustainable transport.