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. Full Article at NBC 11 San Francisco