By Sajid Farooq, Web Producer

Researchers from the University of California, Berkeley and Nokia want to give commuters the ability to navigate through congested highways and obtain road conditions in the palm of their hand.

On Friday the researchers were testing the feasibility of using GPS-enabled mobile phones to monitor real-time traffic flow while preserving the privacy of the phones' users.

One hundred cars were deployed onto a 10-mile stretch of Interstate 880 between Hayward and Fremont for seven hours in the experiment, dubbed "Mobile Century."

The project was funded primarily by the California Department of Transportation.

Each car was equipped with a Nokia N95 mobile phone that ran special software to periodically send anonymous speed-readings from the integrated GPS to servers that then computed traffic conditions.

Information was displayed on the Internet, allowing viewers to visualize traffic in real time.

An independent tracking feature allowed the command center set up in Union City to track the position of the cars to coordinate the experiment and ensure the safety of the drivers.

Using the GPS data to estimate prevailing speeds and travel times, researchers were able to obtain a picture of real-time traffic conditions, the participants said.

Current traffic monitoring systems primarily rely upon pavement-embedded sensors, roadside radar or cameras.

The high cost of installing and maintaining such systems has restricted their coverage to limited stretches of highway.

"For state transportation agencies such as Caltrans, tapping into the vast network of cell phones on the road could one day reduce costs of investing in expensive infrastructure to obtain traffic information," said Randell Iwasaki, Caltrans chief deputy director. "This will greatly expand the coverage of traffic information services so motorists can better plan their trips right on their cell phones."

GPS-based systems can pinpoint a car's location with an accuracy of a few meters and calculate traveling speed to within three miles per hour, according to the researchers.

Enlisting GPS-equipped cell phones into traffic monitoring systems could help provide information on everything from multiple side-street routes in urban areas to hazardous driving conditions or accidents on vast stretches of rural roads, the researchers said.

"There are cell phone-based systems out there that can collect data in a variety of ways, such as measuring signal strength from towers and triangulating positions, but this is the first demonstration of this scale using GPS-enabled mobile phones to provide traffic related data such as travel times, and with a deliberate focus on critical deployment factors such as bandwidth costs and personal privacy issues," said Thomas West, director of UC Berkeley's CCIT.

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

"Even though the phones are capable of sending their position and speed every three seconds, an efficient traffic monitoring system should not need to transfer such a large amount of data, which would require enormous bandwidth," Berkeley researcher Alexandre Bayen said.

Such a powerful system brings up serious questions about cell phone users'privacy, which is why the researchers, with the help of Rutgers University's Winlab, have focused much of the project on mechanisms to protect that privacy

There is currently no projected date for commercial launch of the system.

In the United States alone, traffic congestion leads to 4.2 billion hours in extra travel time and an extra 2.9 billion gallons of fuel burned at a cost of $78 billion, according to a 2007 report from the Texas Transportation Institute.