Data Management in the CarTel Mobile Sensor Network System

                         Samuel Madden, MIT

CarTel is a software and hardware platform for opportunistic sensing
using moving vehicles that has been under development since 2005. Data
is captured from GPS, Wi-Fi, and OBD-II interfaces and stored in a
local database on each car.  This stored data is transferred
opportunistically, via available Wi-Fi networks, cellular modems, or
by "muling" data on a user's cell phone or USB key, to a central
"portal", where users can browse and visualize it.  To allow non-
expert users to specify what data they would like to collect from
remote vehicles, CarTel includes a simple database-like interface for
programming and configuration.

In this talk, I discuss recent developments in the CarTel system,
focusing on applications of the technology to traffic, road surface
quality mapping, and personal commute management, including several
interfaces which provides a map-based interface for browsing thousands
of hours of driving data collected from a fleet of 27 taxicabs that
have been running the software for the past year.  I will also discuss
the database storage and querying challenges presented by the scale
and noisiness of the data collected from CarTel.