GPS Data on Beijing Cabs Reveals the Cause of Traffic Jams

Technology Review has an article on using data from taxi GPS units to try to optimise road design to reduce traffic jams - GPS Data on Beijing Cabs Reveals the Cause of Traffic Jams.

Beijing is a city famous for traffic jams. In 2006, rush hour reportedly lasted 11 hours a day, and the city has been called a "virtual car park" during daylight hours. As in most major cities, urban planners have been trying for years to relieve the pressure by adding new roads or public transit lines, or providing better enforcement for traffic laws.

Now a group working at Microsoft Research Asia has shown that tracking the location of taxicabs could be a better way to identify the underlying problems with a city's transportation network, helping officials determine how to best ease congestion.

The researchers used GPS data from more than 33,000 Beijing taxicabs. That data was collected in 2009 and 2010. The researchers were not just looking for bottlenecks—trouble spots that regular commuters may know only too well. "[Congested] road segments are only the appearance—they're not the problem," says Yu Zheng, who led the research. "We try to identify the true source of the problem in our work."

The researchers presented their work last week at the 13th International Conference on Ubiquitous Computing, which took place in Beijing.

To get at underlying causes of traffic problems, the researchers needed to get information about the trips people are taking—where journeys start, finish, and how a commuter travels in between. The researchers divided Beijing into regions and analyzed the taxi data to find places where two regions weren't properly connected.