Global study maps travel distance to cities

Living near a city means better healthcare, education, and economic opportunities.

Cities give the people living in or near them access to opportunities and services that people in more isolated areas simply don’t have. To see how this access varies around the world, Oxford University researcher Daniel Weiss and his colleagues measured travel times to the nearest city, taking into account not only distance, but also infrastructure like roads. They mapped their results and found that while 90.7 percent of people in high-income countries live within an hour of an urban center, only around 50.7 percent of people in low income countries do. We asked Weiss to tell us more about the project.

ResearchGate: Why is it beneficial to live near a city?

Daniel Weiss: Cities are epicenters of activities that affect human wellbeing, and thus the time (and cost) it requires to reach them impacts the lives of people every day. From commuting to work or school, to accessing healthcare or banking services, ease of access to cities increases the likelihood that people can readily obtain needed goods and services.

RG: What did your study find about travel times to cities?

Weiss: Unsurprisingly, we found that populations in high-income nations, concentrated in Europe and North America, have greater accessibility than populations in low-income nations. More detailed analysis revealed that within low-to-middle income countries, the proximity of people to cities was correlated with higher household income, higher educational attainment, and a greater likelihood of seeking healthcare.

RG: Could infrastructure improvements, like internet access, reduce the burden of living far from a city?

Weiss: Potentially, but cities are great for concentrating activities and people in space, and acting as engines for development via the collaborative potential they provide. It's also worth noting that there is the strong global trend toward greater proportions of people living in cities, so while technological advancements may reduce the burden of living remotely, people continue to demonstrate their belief in the value of cities by moving there.

Travel times to cities, ranging from minutes (bright yellow) to nearly a week (dark purple). Credit: The Malaria Atlas Project, University of Oxford

RG: How do your results compare to past studies, like the map created from 2000 data?

Weiss: The earlier version of the accessibility map was made prior to major improvements in the available dataset this work requires. Roads data in particular has improved dramatically since the earlier version of the map due to the OpenStreetMap project and corporations such as Google. Our work represents the first, global-scale integration of these roads datasets, and the combination of these inputs allowed us to map accessibility with far greater accuracy than was previously possible.

RG: How do you hope your research will be used?

Weiss: Our hope is that this data will reinforce the rather intuitive notion that greater access to cities is beneficial to rural populations, but also make clear that increasing access to very remote area can have negative environmental ramifications. For example, decades of research has shown that constructing a new road through the forests leads to deforestation along the newly built corridor. So, we while we hope our work leads to policy changes that increases access to cities for people, we also hope development occurs sensibly and with consideration for the conservation benefits of remoteness to wilderness areas.

While not especially glamorous, a noteworthy aspect of our accessibility map will be its use as an input into future mapping endeavors. This project actually emerged in response to the need for better input data for our malaria mapping work, but it quickly became apparent that it would have far-reaching utility for other research attempting to map, model, or explain the spatial patterns of the human landscape.

RG: What’s next for you?

Weiss: The next stage of this work will be finishing our online tool that will allow users to make their own accessibility maps to any point features they provide, such as datasets of school or hospital locations. We've freely released our data and code to allow expert users to do this already, but our goal is to allow novice users to create their own maps using just a web browser. Our hope is that this effort will put more data into the hands of decision makers faced with providing services to underserved communities.

Featured image courtesy of The Malaria Atlas Project, University of Oxford