Urban movement linked to social activity

A recent study by researchers uses a new method to infer that most of the urban movement is social, a finding that is applicable consistently in multiple cities.

The study used anonymised phone data from South America and Europe that, unlike most data in the field, provides information that can be used to reconstruct both people's locations and their social networks.

In order to estimate movement in a city, the social component has to be taken into account.

Otherwise, the estimates are going to be off by about 20 percent, showed the study.

"Adding two data sources -- one on the social side and one on the mobility side -- and layering them one on top of each other gives you something that's a little bit greater," said Jameson Toole, a PhD student in Massachusetts Institute of Technology and co-author.

For the study, researchers have successfully built a picture indicating which networks were primarily social, as opposed to work-oriented, and then deduce how much city movement was due to social activity.

By developing a new means of quantifying how much urban travel is based on social activity, they have created a new analytical tool that could be useful to planners and policymakers.

By examining the calls, the networks of calls made, and the times of contact, the team found that most people have three kinds of social networks in cities: social companions, work colleagues and more distant acquaintances with whom people have more sporadic contact.

The researchers were able to quantify the extent to which social activity was the primary cause of an urban trip.

"It is pretty rare you would find these patterns showing up by themselves in multiple cities," Toole said.

The study appeared in the journal Interface.