MOBILE CENTURY-FEBRUARY 8, 2008

Using GPS Mobile Phones as Traffic Sensors: A Field Experiment

Objectives at a glance:

• The experiment will test a novel traffic monitoring system designed to collect velocity and postion data from GPS enabled Nokia N95 cellular phones.

• The data will be used to examine key tradeoffs between preserving user privacy and accuracy of traffic information.

Berkeley -- Researchers from Nokia and the University of California, Berkeley, are testing technology that could soon transform the way drivers navigate through congested highways and obtain information about road conditions. In the field test, transportation researchers will demonstrate the feasibility of using GPS-enabled cell phones to monitor real-time traffic flow.

One hundred vehicles will be deployed onto a 10-mile stretch of highway near San Francisco for 7 hours in the experiment. Each car is equipped with a Nokia N95 mobile phone that regularly sends GPS signals to a central command center throughout the day. Using the data on travel time and speed, researchers will be able to obtain a picture of real-time traffic conditions unlike that available from current technology.

Such phones may one day remove the need to invest in expensive infrastructure to obtain traffic information in both urban and rural areas. Greatly expanding the coverage of traffic information services will give motorists better information to plan their journeys.

Investigators are evaluating such solutions as having the software that aggregates the GPS feeds immediately disassociate the data from an individual device and combine it with the general stream of traffic data. Only anonymous aggregated data is ever created, transported or stored in this "privacy by design" system. All data is further protected by banking-grade encryption.

The goal of the experiment is not only to test the efficiency of the traffic data collection and aggregation system, but to also evaluate the trade-offs between data accuracy, personal privacy and data collection costs.

The benefits of such a system could be huge. In the United States alone, congestion leads to 4.2 billion hours in extra travel time and an extra 2.9 billion gallons of fuel burned for a total cost of $78 billion, according to a 2007 report from the Texas Transportation Institute. With the number of vehicles on the road increasing rapidly around the world, a cost-effective method of travel planning could help drivers make smarter decisions about which routes to take, the researchers say.