“…GPS data crowdsourced through in-car devices is an emerging source of inexpensive data that can be used to provide real-time traffic information, identify traffic patterns, and predict traffic congestions (Cao and Krumm, 2009). This new data collection method is a type of volunteered geographic information that overcomes the high cost of using the traditional intrusive and non-intrusive on-road sensors (e.g., inductive loops) methods, as well as their limitations in data coverage (Grossman et al, 2005). Over the last few years, studies have been done using in-car GPS devices (Yoon et al, 2007;Young, 2007) and more recently with smart phones (Herrera et al, 2010;, to develop data processing techniques, traffic patterns and traffic prediction models, geometric modeling of roads, and generation of road network maps.…”