The IBM work centered on Abidjan, where 539 large buses are supplemented by 5,000 mini-buses and 11,000 shared taxis. The IBM researchers studied call records from about 500,000 phones with data relevant to the commuting question.
Mobility data is created when someone uses a phone for a call or text message. That action is registered on a cell-phone tower and serves as a report on the user’s general location somewhere within the tower’s radius. The person’s movement is then ascertained as the call is transferred to a new tower or when a new call is made that connects to a different tower.
While the data is rough—and of course not everyone on a bus has a phone or is using it—routes can be gleaned by noting the sequence of connections. And IBM and other groups have found that these mobile phone “traces” are accurate enough to serve as a guide to larger population movements for applications such as epidemiology and transportation (see “Big Data from Cheap Phones.”)
The re-routing data could help trim transit times by as much as 10 percent. Neat. (ht Hacker News)