Researchers from Nokia and the University of California in Berkeley will go live with a new project this week that aims to cull GPS data from thousands of mobile phones in order to tell drivers which San Francisco Bay Area roads are backed up and which are moving along.

Called Mobile Millennium, the project will be opened to the public on Monday.

Researchers hope that thousands of volunteers will download a free Java program that figures out by their movement and location when they are driving, and then transmits that information to the project's servers, which then crunch it into a Bay Area traffic map. The software uses algorithms to determine when people are moving or if they are stuck in traffic or stopped by the roadside, for example.

California has already invested heavily in sensors that help monitor traffic conditions on major roadways, but they're not everywhere. By collecting traffic information from GPS (Global Positioning System) phones on roads that don't have sensors, the team hopes to gain insight into places that are now blind spots for most commuters.

Researchers will start by looking for data on heavily trafficked commutes such as Page Mill Road and the Oregon Expressway, which cut through the heart of Palo Alto, California. If enough volunteers download the software, the researchers could eventually build a comprehensive picture of Bay Area traffic conditions.

"The whole concept here is that if everyone shares just a little bit of what they're seeing ... then everyone can benefit by seeing the conditions ahead of them," said Quinn Jacobson, a research leader with Nokia in Palo Alto.

The system doesn't require many users, but it helps if they're spread out, as researchers will need the right concentration of reports. The Mobile Millennium team expects to have 10,000 users by April. "At that rate we'll see many of these arterial roads with accurate, real-time data," Jacobson said.

While the idea of streaming data about their whereabouts may make some people uneasy, researchers say they've taken steps to keep the system anonymous. None of the data in the system can be tied to a particular mobile phone, they said.

The researchers have been testing the traffic reporting system every few weeks over the past year, including a large field-test in February.

Mobile Millennium's data will be available on the Web, but users who want the best data will have to download the Java software, Jacobson said. The software will eventually work on most GPS-enabled phones that run on GSM (Global System for Mobile communications) networks, such as those from T-Mobile and AT&T. On Monday, the software will run on Nokia and BlackBerry phones, but the team expects to add many other devices to this list.

The team is discussing an iPhone port as well, although this will not be available on Monday, Jacobson said.

Because Mobile Millennium phones do a lot of traffic reporting, only users with unlimited data plans are advised to sign up.