Mapping the city, one taxi at a time

A new project at San Francisco’s Exploratorium has started to provide what organizers call an economic, social and cultural map of the city. And they’re doing it by tracking the paths of the city’s cab drivers.

“We noticed Yellow Cab was using global positioning technology instead of the old walkie-talkie system,” says Susan Schwartzenberg, a senior artist at the Exploratorium -- which calls itself the Museum of Science, Art and Human Perception. She and her colleagues persuaded Yellow Cab to give them access to these feeds (courtesy, she says, of “a guy named Lucky who watches cabs all day”). Stamen Design converted the data into a map that’s up at the museum and now at

The result is an unusual map of the city, which shows streets not as they were designed by planners but as they’re actually used in the heat of the moment. “If you watch over time, you see that routes change as the day goes on,” she says. “I don’t see much gridlock because the cab drivers are experienced navigators. They seek out territory where nobody else is going.”

The map shows current and recent cab routes -- slightly delayed in time -- with the immediate past showing up as a kind of ghost image.


“The entire city looks like an organism,” Schwartzenberg says of the similarity of the cab routes to the body’s circulation. On one map, slower routes are white and faster ones are red. “And when you see that pulse going over the Bay Bridge, the whole thing looks like a heart.”

The cab project is part of a larger effort at the museum called Invisible Dynamics, which is built around unearthing hidden systems and urban issues. The goal of the piece, she says, is aesthetic -- to explore the meaning of data and natural systems that otherwise would remain invisible. But the museum has already begun to hear from researchers interested in putting the information to use.

“Does it tell us about geography, does it tell us about communities, does it tell us about desire?” she asks. “Can we use it as a tool for designing streets?” Stay tuned for all that.

One thing we can tell for sure: “The two most dominant lines are the ones that go to the Oakland airport and San Francisco airport. You see the way the system is built around these two base points. We really didn’t know what to expect.”


Scott Timberg