A global map of travel time to cities to assess inequalities in accessibility in 2015

The economic and manmade resources that sustain human wellbeing are not distributed evenly across the world, but are instead heavily concentrated in towns and cities. Poor access to opportunities and services offered by these centers (a function of distance, transport infrastructure, and the spatial distribution of urban centers) is a major barrier to improved livelihoods and overall development. Advancing accessibility worldwide underpins the equity agenda of “leaving no one behind” established by the United Nations’ Sustainable Development Goals (SDGs)1, bringing a renewed international focus on accurately measuring local levels of accessibility and using such assessments to inform development policy design and implementation. The only previous attempt to reliably map accessibility worldwide was conducted nearly a decade ago2, which predated the baseline for the SDGs and excluded the recent and substantial expansion in infrastructure networks, particularly within lower-resource settings. In parallel, new data sources provided by Open Street Map and Google now capture transportation networks with unprecedented detail and precision. By integrating ten global-scale surfaces that characterize factors affecting human movement rates and 13,840 high-density urban centers within an established geospatial-modeling framework we develop and validate a map that quantifies travel time to cities for 2015 at a spatial resolution of approximately 1x1 kilometer. Our results highlight important disparities in accessibility relative to wealth as 50.9% of individuals living in low-income settings (concentrated in sub-Saharan Africa) reside within an hour of a city compared to 90.7% of individuals in high-income settings. By further triangulating this map against key socioeconomic datasets, we demonstrate how access to population centers remains a fundamental determinant that stratifies the economic, educational, and health status of humanity.

WEISS Dan;  NELSON Andrew;  GIBSON Harry;  TEMPERLEY Humphrey William;  PEEDELL Stephen;  LIEBER Allie;  HANCHER Matt;  POYART Eduardo;  BELCHIOR Simao;  FULLMAN Nancy;  MAPPIN B.;  DALRYMPLE Ursula;  ROZIER Jennifer;  LUCAS Tim;  HOWES Rosalind;  TUSTING Lucy;  KANG Su Yun;  CAMERON Ewan;  BISANZIO Donal;  BATTLE Katherine;  BHATT Samir;  GETHING Peter W; 

2018-01-26

NATURE PUBLISHING GROUP

JRC108802

0028-0836,   

https://www.nature.com/articles/nature25181,    https://publications.jrc.ec.europa.eu/repository/handle/JRC108802,   

10.1038/nature25181,