I. Introduction
Having access to road network traffic data is a major need to validate and evaluate indexing and query processing techniques in moving objects databases, spatio-temporal databases, and data streams. Unfortunately, such data is not easily available, and is usually of much smaller scale than needed. The process of extracting real traffic data requires installing and configuring many GPS-enabled devices and continuously monitoring the locations of such devices, which is a cumbersome task. For instance, GeoLife project [13] took more than four years to collect 17,621 trajectories dataset with the involvement of 182 volunteers in Beijing. As a result, researchers have been using existing traffic generators as a means of getting synthetic datasets that exhibit similar behavior to real data. The most two common traffic generators are Brinkhoff [1] and BerlinMOD [3], which have been widely adopted by large numbers of papers in the database literature, e.g., see [2], [5], [6], [8], [10], [12].