Could Cell Phones Stop Traffic?

You're driving down the road. A few miles ahead, a guy in a car talking on his cell phone slows down. Instantly, you know about it and change routes to avoid a traffic jam.

Missouri is trying to put that technology into effect over 5,500 miles of roads.

The Missouri Department of Transportation is negotiating with private contractors to monitor the movement of thousands of cell phones.

Privacy advocates are concerned about a technology that can track people. But transportation and technology leaders say the data gathered will remain anonymous.

The technology doesn't use GPS. Instead, it takes the signals that wireless phones send to towers and follows the movement of the phones from one tower to another. That information is laid over highway maps to draw a grid of where phones are and how fast they're moving.

Presto, you have traffic flow.