There have been stories before about using mobile phone data to analyze automobile traffic patterns, but this is the first time I've heard of it actually being used in practice successfully. Over in Finland, they've been testing a traffic monitoring system that uses mobile phone data to determine where congestion might be. They track the movement of mobile phones based on which towers they're accessing, and determine road speeds from that. They suggest that this is much more accurate than current methods of tracking traffic congestion using sensors and mounted cameras. They admit that there were a few problems with the system - such as assuming that a bus with 30 mobile phone-carrying passengers was 30 cars. Also (and this is a great example) they point out that, "if somebody is picking berries in the woods, it will show up as a stationary item." I didn't know that so many people picked berries next to major thoroughfares, but perhaps it's a Finnish thing. The other big question is about privacy - and the folks behind this program insist that it would be impossible to associate any tracking information with a particular person. However, they do admit that the same technology can be used to track stolen cars - but don't explain how one can be true without the other.