The Missouri Department of Transportation has begun anonymously monitoring cell phone signals as a high-tech way of tracking vehicle speeds and warning motorists of traffic jams. The goal is for motorists to get real-time traffic information over the Internet or road signs. Privacy concerns have slowed down the Missouri project - the largest of its kind nationally - which was supposed to have been deployed statewide by summer 2006 under a contract with Markham, Canada-based Delcan Corp.

Technology firms like Delcan and Atlanta-based AirSage (above) insist their data remain anonymous, leaving no way to track specific people from their driveway to their destination. The technology uses cellular signals to track car movements. Then it overlays that data with highway maps to estimate where the phones are and how fast they are moving. Lumping thousands of those signals together can indicate traffic flow. Many cities and states already measure traffic speeds and volumes by embedding sensors in pavement or mounting scanners along the road. But those methods can be expensive and take only a snapshot of traffic at a particular spot.

A recent study at Florida International University said nearly 30 companies and organizations claim to have the capability to provide real-time traffic data based on anonymous information gleaned from cell phones. But “the cell phone technology is not accurate in congested traffic conditions, where the data is more important than in the free-flow traffic conditions, and the accuracy decreases rapidly as the congestion increases,” according to the Florida report from this April. When it won the Missouri contract in December 2005, Delcan planned on using data from Cingular Wireless. But before the project could ever get started, Cingular opted out. “The cell phone company thought it just wasn’t worth the risk that the public might perceive their personal information was being used that way.”

The Electronic Privacy Information Center (EPIC) raised concerns a couple years ago that once the cell phone data is collected and shared, it could end up being used for other government purposes such as law enforcement centers. Despite assurances to the contrary from the technology’s proponents, those concerns remain, said Lillie Coney, EPIC’s associate director. “The mission creep potential is there,” Coney said. “There are other ways of figuring out traffic patterns without having to go to something that’s so identifiable as a cell phone.”

It’s sounds similar to Celldar which exploits the RF signals radiated from ordinary cell base stations. BAE SYSTEMS and Roke Manor Research are teaming to develop CELLphone raDAR. Everything that moves can be tracked after subtracting static reflections. Lockheed-Martin is perhaps the best-known passive-radar champion, but others include Avtec Systems, Dynetics, and ONERA, the French counterpart of NASA. Lockheed-Martin’s system is dubbed Silent Sentry which tracked all air traffic over Washington, D.C., using FM and TV transmitters.