Mapping Accessibility with the 15 Min City Platform

In September 2024 (and recently reported on by The Economist), Sony Computer Science Laboratories produced 15 Min City (view here), a platform that uses OpenSteetMap data to estimate accessibility of services by foot/bike, grouped by the following: 

1. Outside activities: parks, walks, picnics 
2. Learning: schools, universities 
3. Supplies: supermarkets, grocery stores 
4. Eating: restaurants, bistros, cafes 
5. Moving: bus stations, train stations, taxis 
6. Cultural Activities: museums, theatres, cinemas 
7. Physical Exercise: gyms, sports centres 
8. Services: offices, banks, post office, town halls 
9. Healthcare: hospitals, doctors, pharmacies 

Unlike previous similar models, 15 Min City holds data for over 4,000 cities from all around the world. Score for cities and neighbourhoods (each an approx. 10ha hexagon) can be viewed as an average of all 9 services or picking a single service type. Scores are calculated based on the average time it takes to reach the 20 closest Points of Interest for each specific service type. 

The scale of the work means that it’s far from perfect, but it provides a valuable new view of many of the cities in which we work. For Reall, this tool could help identify service gaps in different neighbourhoods and help assess the suitability of different project locations. In the images below, we have used our Projects Dashboard to overlay Reall projects across 15 Min City data from two of the cities in which we have undertaken the most work; Mumbai and Nairobi.  

In Mumbai, our work with SSNS on the Transferable Development Rights model meant that we were able to deliver in-situ redevelopment in some of the densest neighbourhoods in the city. Bharat Janta and Rajiv Indira form part of Dharavi, which is both one of the world’s largest slums and some of the most valuable real estate in the city, demonstrated by the ongoing US$3bn redevelopment plans. The only Mumbai project not delivered through this model was Milan Nagar, which provided homes to pavement dwellers, in a new location right on the edge of the city. At first there was very little available to residents in terms of services. This location has developed significantly in the two decades since the project was completed but remains significantly worse connected than the other Mumbai projects. 

In Nairobi, we have delivered three different models over the past 20 years. In 2005, we worked with very low-income communities in informal settlements to provide in-situ housing. These settlements remain low-income areas with limited infrastructure and poor-quality roads (see Kambi Moto, Gitathuru and Mahira), but easy access to services. In 2021, we invested in two projects with KKL to provide low cost prefabricated rental units on small plots of land for backyard landlords (Kawagware and Kawangware 2) in lower income/informal settlements, again providing very good access to services. In 2020, we invested in Zima Homes, a medium-rise apartment block that is more similar to Reall’s standard model. As it required private purchase of land large enough to fit 136 apartments, it was unsurprisingly located on the outskirts of Nairobi, next to a main road into the city but with limited access to services by bicycle or foot.  

Access to services only provides part of the overall picture; locations such as Wangige provide cleaner, safer, more pollution-free living. Direct, rapid, public transport can mitigate many of the problems from being located in poorer-serviced areas, and as we saw from Milan Nagar, cities are built around projects over time and services improve. However, this development takes time and the costs of daily travel can be considerable; we saw from many of our previous projects around Nairobi that (particularly in early years) residents found the commute to their city-based jobs too challenging and so would rent rooms in the slums during the week and only spend weekends in their new homes outside of the city. This created challenges in making payments for their new homes (they were paying for two places to live after all), which impacted the financial viability of these projects. This started to change over time as residents were able to move to jobs closer to their homes, but on some projects, it remains an issue. 

There will always be conflict between location and cost of land for affordable housing, and there is no single solution. The 15 Min City platform is a great way of visualising these challenges and highlights the need for connected cities: without access to essential services and integration into well-planned networks for economic growth, affordable homes are often no longer affordable. 

By Ben Atkinson, Programme Lead – Data and Evidence