In a new paper, published in Nature Human Behaviour, scientists from DTU (the Technical University of Denmark) examine how geography shapes human mobility and propose a way to separate physical constraints from behavioural patterns. A result that may improve urban planning, transportation design as well as epidemiology models.

Using 36 years of detailed residential relocation data from Denmark, which covers 39 million moves, between more than three million addresses, the researchers show that when you account for the influence of geography, the likelihood of moving decreases consistently with distance. This means, roughly speaking, that if you double the distance, the likelihood of people moving there is half. In cities, however, distance matters less.

The reader would be right in thinking this result seems obvious. But from a scientific perspective, the data describing these several million moves was anything but simple.

"Looking at how people have moved, it was initially hard to understand. It didn’t follow any clear pattern," says Sune Lehmann, corresponding author and professor at DTU.

"For example, we saw a lot of moves at around 180 kilometres, while other distances were not observed nearly as often. But if you think about where you can actually move, there are certain places that people flock to, while others are completely inaccessible. When we look at a map, it may look like we can go anywhere, but we are actually only using a very small part of the country.”