Date Added: Mar 2011
Traffic monitoring using probe vehicles with GPS receivers promises significant improvements in cost, coverage, and accuracy over dedicated infrastructure systems. Current approaches, however, raise privacy concerns because they require participants to reveal their positions to an external traffic monitoring server. To address this challenge, the authors describe a system based on virtual trip lines and an associated cloaking technique, followed by another system design in which they relax the privacy requirements to maximize the accuracy of real-time traffic estimation. They introduce virtual trip lines which are geographic markers that indicate where vehicles should provide speed updates. These markers are placed to avoid specific privacy sensitive locations.