Frequently Asked Questions
Q: How does this work?
A: Yellow Cab is one of a number of taxi companies which uses GPS
technology to track the locations of their taxis as they drive around
the city. Once every minute or so, each cab reports it’s location to
the central dispatch. As orders for pick ups come in over the phone,
these addresses are automatically passed to drivers, depending on how
close they are. This location data is usually discarded after being
reported – but Yellow Cab has generously allowed us to capture this
information over time, allowing the generation of the maps you see on
this site. See the About page for more information.

Q: How are you addressing privacy concerns with this project?
A: Out of respect for the privacy of cab drivers and customers, no
direct access to cab data with identifiable cab numbers is provided to
the public or to our artists. The project emphasizes the analysis of
aggregate data and data patterns, with most of this analysis happening
on historic data and larger data patterns using scrambled cab numbers.
Real-time information is limited to a small sample of random cabs. The
display resolution is also limited to prevent tracking to and from
individual addresses. We welcome comments and suggestions on how to
restrict the system to a benevolent use of the data.

Q: I would like to create an artist’s project – how do I do it?
A: You are welcome, and encouraged, to make your own interpretation or
analysis of this data at any time and post it to your own website or
blog. If you would like a link or a copy of your work included on this
site, please contact the webmaster:

Q: I would like to create my own Cabspotting client – how do I do it?
A: Please contact: for the instructions on writing to
our API and for the open source Flash example client.

Q: Do you have any good ideas for a project or client?
A: Why yes! Some suggestions are:

A client that correlates cab rides with zip code and average income to
show the relationship between socioeconomic status and use of cabs
using graphs, diagrams and narrative analysis of sociological and
economic patterns.

Tracking an individual ride and documenting it with photos, drawings,
sound recordings or video. Combine this information with the cab path
extracted from the day’s record to form a small portrait.

Examine the points where cabs rarely or never visit and explore why
this is through photographs, interviews and historical research.

Examine the most frequently visited places (outside of airports and
hotels) in a similar manner.

Showing all the cab rides that pass in front of a specific place during
one day.

A client that warps the bay area map based on the frequency of cab
visits, distorting the landscape to create a “cab-centric” view.

A client that highlights the most eccentric paths, such as the very
short, long or circuitous.

Document earlier bay-area cab events and reconstruct them with the
Cabspotting client. For example: “Mel Henderson did some terrific
pieces in the ’60s-one was a Yellow Cab piece, where we all hired a cab
in San Francisco and went to a certain location at a certain hour. And
all these cabs started converging, and the neighborhood became yellow.
It was terrific. Too bad for anybody who was trying to get to the
airport that day” (From conversation w/ Jim Melchert)